Biphenyl compounds useful as muscarinic receptor antagonists

ABSTRACT

This invention provides compounds of formula I: 
                         
wherein a, b, c, d, m, n, p, s, t, Ar 1 , R 1 , R 2 , R 3 , R 4 , R 6 , R 7 , R 8 , and W are as defined in the specification. The compounds of formula I are muscarinic receptor antagonists. The invention also provides pharmaceutical compositions containing such compounds, processes and intermediates for preparing such compounds and methods of using such compounds to treat pulmonary disorders.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Ser. No. 12/328,033, filed Dec. 4, 2008, now allowed, which in turn is a divisional application of U.S. Ser. No. 11/077,436, filed Mar. 10, 2005, now U.S. Pat. No. 7,560,469, which claims the benefit of U.S. Provisional Application No. 60/552,264, filed on Mar. 11, 2004; the entire disclosures of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to novel biphenyl compounds having muscarinic receptor antagonist or anticholinergic activity. This invention also relates to pharmaceutical compositions comprising such biphenyl compounds, processes and intermediates for preparing such biphenyl compounds and methods of using such biphenyl compounds to treat pulmonary disorders.

2. State of the Art

Pulmonary or respiratory disorders, such as chronic obstructive pulmonary disease (COPD) and asthma, afflict many millions of people worldwide and such disorders are a leading cause of morbidity and mortality.

Muscarinic receptor antagonists are known to provide bronchoprotective effects and therefore, such compounds are useful for treating respiratory disorders, such as COPD and asthma. When used to treat such disorders, muscarinic receptor antagonists are typically administered by inhalation. However, even when administered by inhalation, a significant amount of the muscarinic receptor antagonist is often absorbed into the systemic circulation resulting in systemic side effects, such as dry mouth, mydriasis and cardiovascular side effects.

Additionally, many inhaled muscarinic receptor antagonists have a relatively short duration of action requiring that they be administered several times per day. Such a multiple-daily dosing regime is not only inconvenient but also creates a significant risk of inadequate treatment due to patient non-compliance with the required frequent dosing schedule.

Accordingly, a need exists for new muscarinic receptor antagonists. In particular, a need exists for new muscarinic receptor antagonists that having high potency and reduced systemic side effects when administered by inhalation. Additionally, a need exists for inhaled muscarinic receptor antagonists having a long duration of action thereby allowing for once-daily or even once-weekly dosing. Such compounds are expected to be particularly effective for treating pulmonary disorders, such as COPD and asthma, while reducing or eliminating side effects, such as dry-mouth and constipation.

SUMMARY OF THE INVENTION

The present invention provides novel biphenyl compounds having muscarinic receptor antagonist or anticholinergic activity. Among other properties, compounds of the invention are expected to possess high potency and reduced systemic side effects when administered by inhalation and to have a long duration of action.

Accordingly, in one of its composition aspects, this invention provides a compound of formula I:

wherein:

a is 0 or an integer of from 1 to 5;

each R¹ is independently selected from (1-4C)alkyl, (2-4C)alkenyl, (2-4C)alkynyl, (3-6C)cycloalkyl, cyano, halo, —OR^(1a), —C(O)OR^(1b), —SR^(1c), —S(O)R^(1d), —S(O)₂R^(1e), —NR^(1f)R^(1g), —NR^(1h)S(O)₂R^(1i), and —NR^(1i)C(O)R^(1k); where each of R^(1a), R^(1b), R^(1c), R^(1d), R^(1e), R^(1f), R^(1g), R^(1h), R^(1i), R^(1j), and R^(1k) is independently hydrogen, (1-4C)alkyl or phenyl(1-4C)alkyl;

b is 0 or an integer of from 1 to 4;

each R² is independently selected from (1-4C)alkyl, (2-4C)alkenyl, (2-4C)alkynyl, (3-6C)cycloalkyl, cyano, halo, —OR^(2a), —C(O)OR^(2b), —SR^(2c), —S(O)R^(2d), —S(O)₂R^(2e), —NR^(2f)R^(2g), —NR^(2h)S(O)₂R^(2i), and —NR^(2j)C(O)R^(2k); where each of R^(2a), R^(2b), R^(2c), R^(2d), R^(2e), R^(2f), R^(2g), R^(2h), R^(2i), R^(2j), and R^(2k) is independently hydrogen, (1-4C)alkyl or phenyl(1-4C)alkyl;

W represents O or NW^(a), where W^(a) is hydrogen or (1-4C)alkyl;

c is 0 or an integer from 1 to 5;

each R³ independently represents (1-4C)alkyl or two R³ groups are joined to form (1-3C)alkylene, (2-3C)alkenylene or oxiran-2,3-diyl;

m is 0 or 1;

R⁴ is selected from hydrogen, (1-4C)alkyl, and (3-4C)cycloalkyl;

s is 0, 1 or 2;

Ar¹ represents a phenylene group or a (3-5C)heteroarylene group containing 1 or 2 heteroatoms selected independently from oxygen, nitrogen or sulfur; wherein the phenylene or heteroarylene group is substituted with (R⁵)_(q) where q is 0 or an integer from 1 to 4 and each R⁵ is selected independently from halo, hydroxy, (1-4C)alkyl or (1-4C)alkoxy;

t is 0, 1 or 2;

n is 0 or an integer from 1 to 3;

d is 0 or an integer from 1 to 4;

each R⁶ independently represents fluoro or (1-4C)alkyl;

p is 0 or 1; and

R⁷ and R⁸ are independently hydrogen or (1-4C)alkyl;

wherein each alkyl and alkoxy group in R¹, R^(1a-1k), R², R^(2a-2k), R³, R⁵, R⁶, R⁷, and R⁸ is optionally substituted with 1 to 5 fluoro substituents;

or a pharmaceutically acceptable salt or solvate or stereoisomer thereof.

In another of its composition aspects, this invention is directed to a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt or solvate or stereoisomer thereof. Such pharmaceutical compositions may optionally contain other therapeutic agents. Accordingly, in one embodiment, this invention is directed to such a pharmaceutical composition wherein the composition further comprises a therapeutically effective amount of a steroidal anti-inflammatory agent, such as a corticosteroid; a β₂ adrenergic receptor agonist; a phosphodiesterase-4 inhibitor; or a combination thereof.

Compounds of this invention possess muscarinic receptor antagonist activity. Accordingly, compounds of formula I are expected to be useful for treating pulmonary disorders, such as chronic obstructive pulmonary disease and asthma.

Accordingly, in one of its method aspects, this invention is directed to a method for treating a pulmonary disorder, the method comprising administering to a patient a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt or solvate or stereoisomer thereof.

Additionally, in another of its method aspects, this invention is directed to a method of producing bronchodilation in a patient, the method comprising administering to a patient a bronchodilation-producing amount of a compound of formula I or a pharmaceutically acceptable salt or solvate or stereoisomer thereof.

This invention is also directed to a method of treating chronic obstructive pulmonary disease or asthma, the method comprising administering to a patient a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt or solvate or stereoisomer thereof.

In another one of its method aspects, this invention is directed to a method for antagonizing a muscarinic receptor in a mammal comprising administering to the mammal, a therapeutically effective amount of the compound of formula I.

Since compounds of this invention possess muscarinic receptor antagonist activity, such compounds are also useful as research tools. Accordingly, in yet another of its method aspects, this invention is directed to a method for using a compound of formula I or a pharmaceutically acceptable salt or solvate or stereoisomer thereof as a research tool for studying a biological system or sample, or for discovering new chemical compounds having muscarinic receptor antagonist activity.

This invention is also directed to processes and novel intermediates useful for preparing compounds of formula I or a pharmaceutically acceptable salt or solvate or stereoisomer thereof. Accordingly, in another of its method aspects, this invention is directed to a process of preparing a compound of formula I, the process comprising:

-   -   (a) reacting a compound of formula II with a compound of formula         III;     -   (b) coupling a compound of formula IV with a compound of formula         V;     -   (c) reacting a compound of formula VI with a compound of formula         VII;     -   (d) reacting a compound of formula II with a compound of formula         VIII in the presence of a reducing agent;     -   (e) reacting a compound of formula IX with a compound of formula         VII in the presence of a reducing agent; or     -   (g) for a compound of formula I in which m is 0, reacting a         compound of formula II with a compound of formula X;         and then removing any protecting groups, if necessary, to         provide a compound of formula I; wherein compounds of formula         I-X are as defined herein.

In one embodiment, the above process further comprises the step of forming a pharmaceutically acceptable salt of a compound of formula I. In other embodiments, this invention is directed to the other processes described herein; and to the product prepared by any of the processes described herein.

This invention is also directed to a compound of formula I or a pharmaceutically acceptable salt or solvate or stereoisomer thereof, for use in therapy or as a medicament.

Additionally, this invention is directed to the use of a compound of formula I or a pharmaceutically acceptable salt or solvate or stereoisomer thereof, for the manufacture of a medicament; especially for the manufacture of a medicament for the treatment of a pulmonary disorder or for antagonizing a muscarinic receptor in a mammal.

DETAILED DESCRIPTION OF THE INVENTION

In one of its composition aspects, this invention is directed to novel biphenyl compounds of formula I or pharmaceutically acceptable salts or solvates or stereoisomers thereof. These compounds may contain one or more chiral centers and therefore, this invention is directed to racemic mixtures; pure stereoisomers (i.e., enantiomers or diastereomers); stereoisomer-enriched mixtures and the like unless otherwise indicated. When a particular stereoisomer is shown or named herein, it will be understood by those skilled in the art that minor amounts of other stereoisomers may be present in the compositions of this invention unless otherwise indicated, provided that the desired utility of the composition as a whole is not eliminated by the presence of such other isomers.

The compounds of formula I also contain several basic groups (e.g., amino groups) and therefore, the compounds of formula I can exist as the free base or in various salt forms. All such salt forms are included within the scope of this invention. Furthermore, solvates of compounds of formula I or salts thereof are included within the scope of this invention.

Additionally, where applicable, all cis-trans or E/Z isomers (geometric isomers), tautomeric forms and topoisomeric forms of the compounds of formula I are included within the scope of this invention unless otherwise specified.

The compounds of formula I, as well as those compounds used in its synthesis, may also include isotopically-labeled compounds, i.e., where one or more atoms have been enriched with atoms having an atomic mass different from the atomic mass predominately found in nature. Examples of isotopes that may be incorporated into the compounds of Formula (I) include, but are not limited to, ²H, ³H, ¹³C, ¹⁴C, ¹⁵N, ¹⁸O and ¹⁷O.

The nomenclature used herein to name the compounds of this invention is illustrated in the Examples herein. This nomenclature has been derived using the commercially-available AutoNom software (MDL, San Leandro, Calif.).

Representative Embodiments

The following substituents and values are intended to provide representative examples of various aspects and embodiments of this invention. These representative values are intended to further define and illustrate such aspects and embodiments and are not intended to exclude other embodiments or to limit the scope of this invention. In this regard, the representation that a particular value or substituent is preferred is not intended in any way to exclude other values or substituents from this invention unless specifically indicated.

The values for a and b are independently 0, 1, 2, 3, 4 or 5; particularly independently 0, 1 or 2, and even more particularly 0 or 1. In one embodiment, both a and b are 0.

When present, each R¹ may be at the 2, 3, 4, 5 or 6-position of the phenyl ring to which it is attached. Each R¹ is independently selected from (1-4C)alkyl, (2-4C)alkenyl, (2-4C)alkynyl, (3-6C)cycloalkyl, cyano, halo, —OR^(1a), —C(O)OR^(1b), —SR^(1c), —S(O)R^(1d), —S(O)₂R^(1e), —NR^(1f)R^(1g), —NR^(1h)S(O)₂R^(1i), and —NR^(1j)C(O)R^(1k), examples of which include methyl, fluoro, chloro, bromo, hydroxy, methoxy, amino, methylamino, dimethylamino and the like. In one embodiment, each R¹ is independently selected from (1-4C)alkyl, halo, —OR^(1a) and —NR^(1f)R^(1g). Particular values for R¹ are fluoro or chloro.

When present, each R² may be at the 3, 4, 5 or 6-position on the phenylene ring to which it is attached (where the carbon atom on the phenylene ring attached to the nitrogen atom is position 1). Each R² is independently selected from (1-4C)alkyl, (2-4C)alkenyl, (2-4C)alkynyl, (3-6C)cycloalkyl, cyano, halo, —OR^(2a), —C(O)OR^(2b), —SR^(2c), —S(O)R^(2d), —S(O)₂R^(2e), —NR^(2f)R^(2g), —NR^(2h)S(O)₂R^(2i), and —NR^(2j)C(O)R^(2k), examples of which include methyl, fluoro, chloro, bromo, hydroxy, methoxy, amino, methylamino, dimethylamino and the like. In one embodiment, each R² is independently selected from (1-4C)alkyl, halo, —OR^(2a) and —NR^(2f)R^(2g). Particular values for R² are fluoro or chloro.

Each R^(1a), R^(1b), R^(1c), R^(1d), R^(1e), R^(1f), R^(1g), R^(1h), R^(1i), R^(1j), and R^(1k) and R^(2a), R^(2b), R^(2c), R^(2d), R^(2e), R^(2f), R^(2g), R^(2h), R^(2i), R^(2j), and R^(2k) as used in R¹ and R², respectively, is independently hydrogen, (1-4C)alkyl or phenyl(1-4C)alkyl, examples of which include hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl or benzyl. In one embodiment, these groups are independently hydrogen or (1-3C)alkyl. In another embodiment, these groups are independently hydrogen, methyl or ethyl. In addition, each alkyl and alkoxy group in R¹, R^(1a-1k), R², and R^(2a-2k) is optionally substituted with 1 to 5 fluoro substituents.

In one embodiment of this invention, W is O. In another embodiment, W is NW^(a). Generally, it has been found that compounds in which W represents O exhibit particularly high affinity for muscarinic receptors. Accordingly, in a particular embodiment of this invention, W represents O.

When W is NW^(a), W^(a) is hydrogen or (1-4C)alkyl, examples of which include hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. In one embodiment, W^(a) is hydrogen or (1-3C)alkyl. In another embodiment, W^(a) is hydrogen, methyl or ethyl, particularly hydrogen or methyl. In yet another embodiment, W^(a) is hydrogen and NW^(a) is NH.

The value for c is 0, 1, 2, 3, 4, or 5; particularly 0, 1, or 2; and more particularly 0 or 1. In one particular embodiment, c is 0. In another embodiment, c is 2.

Each R³ independently represents (1-4C)alkyl or two R³ groups that are joined to form (1-3C)alkylene, (2-3C)alkenylene or oxiran-2,3-diyl. In one embodiment, each R³ is independently (1-4C)alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. In addition, each alkyl group in R³ is optionally substituted with 1 to 5 fluoro substituents. In one embodiment, each R³ is independently (1-3C) alkyl, and in another embodiment, each R³ is independently methyl or ethyl.

In one embodiment, each R³ is at the 3, 4 or 5-position on the piperidine ring (where the nitrogen atom of the piperidine ring is position 1). In a particular embodiment, R³ is at the 4-position on the piperidine ring. In another embodiment, R³ is at the 1-position of the piperidine ring, i.e., on the nitrogen atom of the piperidine ring thus forming a quaternary amine salt.

In yet another embodiment, two R³ groups are joined to form a (1-3C)alkylene or (2-3C)alkenylene group. For example, two R³ groups at the 2 and 6-positions on the piperidine ring can be joined to form an ethylene bridge (i.e., the piperidine ring and the R³ groups form an 8-azabicyclo[3.2.1]octane ring); or two R³ groups at the 1 and 4-positions on the piperidine ring can be joined to form an ethylene bridge (i.e., the piperidine ring and the R³ groups form an 1-azabicyclo[2.2.2]octane ring). In this embodiment, other R³ groups as defined herein may also be present.

In still another embodiment, two R³ groups are joined to form a oxiran-2,3-diyl group. For example, two R³ groups at the 2 and 6-positions on the piperidine ring can be joined to form a 3-oxatricyclo[3.3.1.0^(2,4)]nonane ring). In this embodiment, other R³ groups as defined herein may also be present.

The value for m is 0 or 1. In one embodiment, m is 0.

R⁴ represents hydrogen, (1-4C)alkyl, or (3-4C)cycloalkyl. Examples of (1-4C)alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. Examples of (3-4C)cycloalkyl groups include cyclopropyl and cyclobutyl. In one embodiment, R⁴ is hydrogen or methyl. In another embodiment, R⁴ is hydrogen.

The value for s is 0, 1 or 2. A particular value for s is 0 or 1. In one embodiment, s is O.

Ar¹ is a phenylene group or a (3-5C)heteroarylene group containing 1 or 2 heteroatoms selected independently from oxygen, nitrogen or sulfur. The phenylene or heteroarylene group may be unsubstituted (q is 0) or substituted with 1, 2, 3, or 4 (q is 1, 2, 3, or 4) R⁵ substituents, which are independently selected from halo, hydroxy, (1-4C)alkyl or (1-4C)alkoxy. In addition, each alkyl and alkoxy group in R⁵ is optionally substituted with 1 to 5 fluoro substituents. The point of attachment is at any available carbon or heteroatom ring atom. In certain embodiments, Ar¹ is a phenylene group attached at the meta or para position.

In one embodiment Ar¹ is phen-1,3-ylene or phen-1,4-ylene wherein the phenylene group is unsubstituted or substituted with 1, 2 or 3 R⁵ substituents. Representative R⁵ substituents include hydroxy, fluoro, chloro, bromo, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, methoxy, ethoxy, isopropoxy, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl and trifluoromethoxy. Particular examples of Ar¹ groups in this embodiment include 2-fluorophen-1,4-ylene, 3-fluorophen-1,4-ylene, 2-chlorophen-1,4-ylene, 3-chlorophen-1,4-ylene, 2-methylphen-1,4-ylene, 3-methylphen-1,4-ylene, 2-methoxyphen-1,4-ylene, 3-methoxyphen-1,4-ylene, 2-trifluoromethoxyphen-1,4-ylene, 3-trifluoromethoxyphen-1,4-ylene, 2,3-difluorophen-1,4-ylene, 2,5-difluorophen-1,4-ylene, 2,6-difluorophen-1,4-ylene, 2,3-dichlorophen-1,4-ylene, 2,5-dichlorophen-1,4-ylene, 2,6-dichlorophen-1,4-ylene, 2-chloro-5-methoxyphen-1,4-ylene, 2-chloro-6-methoxyphen-1,4-ylene, 2-chloro-5-trifluoromethoxyphen-1,4-ylene, and 2-chloro-6-trifluoromethoxyphen-1,4-ylene.

In another embodiment, Ar¹ is a (3-5C)heteroarylene group containing 1 or 2 heteroatoms selected independently from oxygen, nitrogen or sulfur; wherein the heteroarylene group is unsubstituted or substituted with 1 or 2 R⁵ substituents. Representative heteroarylene groups include divalent species of pyrrole, imidazole, thiazole, oxazole, furan, thiophene, pyrazole, isoxazole, isothiazole, pyridine, pyrazine, pyridazine and pyrimidine, where the point of attachment is at any available carbon or nitrogen ring atom. More specific examples of such Ar¹ groups include 2,5-furylene, 2,4-thienylene, 2,5-thienylene, 2,5-pyridylene, 2,6-pyridylene, and 2,5-pyrrolylene. Representative R⁵ substituents include fluoro, chloro, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, methoxy, ethoxy, isopropoxy, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl and trifluoromethoxy. Particular examples of substituted Ar¹ groups include 3-fluoro-2,5-thienylene, 3-chloro-2,5-thienylene, 3-methyl-2,5-thienylene, 3-methoxy-2,5-thienylene, and 3-methoxy-6-chloro-2,5-pyridylene.

In one particular embodiment, Ar¹ represents phen-1,3-ylene, phen-1,4-ylene, 2,4-thienylene, 2,5-thienylene, 2,5-furylene, 2,5-pyridylene, 2,6-pyridylene, or 2,5-pyrrolylene; wherein the phenylene, thienylene, furylene, pyridylene or pyrrolylene group is optionally substituted with 1 or 2 R⁵ substituents.

The value for q is 0, 1, 2, 3, or 4, particularly 0, 1, 2 or 3. In one embodiment, q is 0 or 1.

The value for t is 0, 1 or 2. A particular value for t is 1.

The value for n is 0, 1, 2, or 3. Particular values for n are 1 or 2. In one embodiment, n is 2.

The value for d is 0, 1, 2, 3, or 4. Particular values for d are 0, 1 or 2. In one embodiment, d is 0.

Each R⁶ independently represents fluoro or (1-4C)alkyl, examples of which include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. In addition, each alkyl and alkoxy group in R⁶ is optionally substituted with 1 to 5 fluoro substituents. In one embodiment, each R⁶ independently represents fluoro or (1-sC)alkyl, and in another embodiment, each R⁶ is independently selected from fluoro, methyl, ethyl or trifluoromethyl.

The value for p is 0 or 1. In one particular embodiment, p is 0.

R⁷ and R⁸ each independently represent hydrogen or (1-4C)alkyl, examples of which include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. In one embodiment, R⁷ and R⁸ each independently represent hydrogen or (1-3C)alkyl. In a particular embodiment, R⁷ is hydrogen, methyl, ethyl, n-propyl or isopropyl, and R⁸ is hydrogen. In another particular embodiment, R⁷ and R⁸ are both ethyl. In addition, each alkyl and alkoxy group in R⁷ and R⁸ is optionally substituted with 1 to 5 fluoro substituents.

As noted in formula I, the —CONR⁷R⁸ group can be located at any carbon atom on the ring. For example, when n is 2, the —CONR⁷R⁸ group can be located at the ortho, meta or para position. In one embodiment, the —CONR⁷R⁸ group is located at the meta or para position; and in a particular embodiment, the —CONR⁷R⁸ group is located at the para position.

Representative Subgeneric Groupings

The following subgeneric formulae and groupings are intended to provide representative examples of various aspects and embodiments of this invention and as such, they are not intended to exchide other embodiments or to limit the scope of this invention unless otherwise indicated.

A particular group of compounds of interest are compounds of formula I wherein a, b, and c are 0. Another group of compounds of interest are compounds of formula I wherein W represents O. Another group of compounds of interest are compounds of formula I wherein m and s are 0, and t is 1. Another group of compounds of interest are compounds of formula I wherein —CONR⁷R⁸ group is in the para position, d and p are 0, and n is 2. Another group of compounds of interest are compounds of formula I wherein Ar¹ represents phen-1,4-ylene, wherein the phenylene group is optionally substituted with one or two R⁵ substituents. Another group of compounds of interest are compounds of formula I wherein R⁴ is hydrogen or methyl. Combinations of the foregoing are also of interest. For example, one group of compounds of interest are compounds of formula I wherein a, b, c, d, m, p, and s each represent 0; n is 2; t is 1; W represents 0; Ar¹ represents phen-1,4-ylene optionally substituted with one or two R⁵ substituents; and the —CONR⁷R⁸ group is in the para position.

Another particular group of compounds of interest are compounds of formula I, where a, b, c, d, m, p, and s are 0; t is 1; n is 2; W is O; Ar¹ is 1,4-phenylene; and R⁸ is hydrogen. These compounds have the formula Ia:

wherein R⁴, R⁵, R⁷ and q are as defined herein; or a pharmaceutically acceptable salt or solvate or stereoisomer thereof.

Another particular group of compounds of interest are compounds of formula Ia, where q is 0; or q is 1 or 2 and R⁵ is selected independently from hydroxy, halo, (1-4C)alkyl or (1-4C)alkoxy, wherein each alkyl and alkoxy group is optionally substituted with from 1 to 3 fluoro substituents.

A particular group of compounds of formula I are those disclosed in U.S. Provisional Application No. 60/552,264, filed on Mar. 11, 2004. This group includes compounds of formula I′:

wherein:

a is 0 or an integer of from 1 to 3; each R¹ is independently selected from (1-4C)alkyl, (2-4C)alkenyl, (2-4C)alkynyl, (3-6C)cycloalkyl, cyano, halo, —OR^(1a), —C(O)OR^(1b), —SR^(1c), —S(O)R^(1d), —S(O)₂R^(1e) and —NR^(1f)R^(1g); each of R^(1a), R^(1b), R^(1c), R^(1d), R^(1e), R^(1f) and R^(1g) is independently hydrogen, (1-4C)alkyl or phenyl-(1-4C)alkyl;

b is 0 or an integer of from 1 to 3; each R² is independently selected from (1-4C)alkyl, (2-4C)alkenyl, (2-4C)alkynyl, (3-6C)cycloalkyl, cyano, halo, —OR^(2a), —C(O)OR^(2b), —SR^(2c), —S(O)R^(2d), —S(O)₂R^(2e) and —NR^(2f)R^(2g); each of R^(2a), R^(2b), R^(2c), R^(2d), R^(2e), R^(2f) and R^(2g) is independently hydrogen, (1-4C)alkyl or phenyl-(1-4C)alkyl;

W represents O or NW^(a), where W^(a) is hydrogen or (1-4C)alkyl;

c is 0 or an integer from 1 to 4; each R³ independently represents (1-4C)alkyl;

m is 0 or 1;

R⁴ is hydrogen or (1-4C)alkyl;

s is 0 or 1;

Ar¹ represents a phenylene group or a (3-5C)heteroarylene group containing 1 or 2 heteroatoms selected independently from oxygen, nitrogen or sulfur; wherein the phenylene or heteroarylene group is substituted with (R⁵)_(q) where q is 0 or an integer from 1 to 4 and each R⁵ is selected independently from halo, hydroxy, (1-4C)alkyl or (1-4C)alkoxy;

t is 0 or 1;

n is 0, 1 or 2;

d is 0 or an integer from 1 to 4; each R⁶ independently represents fluoro or (1-4C)alkyl; and

R⁷ is hydrogen or (1-4C)alkyl;

wherein each alkyl and alkoxy group in R¹, R^(1a-1g), R², R^(2a-2g), R³, R⁵, R⁶ or R⁷ is optionally substituted with 1 to 5 fluoro substituents; or a pharmaceutically acceptable salt or solvate or stereoisomer thereof.

Another particular group of compounds of interest are compounds of formula I′ where a, b, c, d, m, and s are 0; t is 1; W is O; and Ar¹ is 1,4-phenylene.

Particular compounds of interest include:

-   biphenyl-2-ylcarbamic acid     1-{2-[4-(4-carbamoylpiperidin-1-ylmethyl)phenyl     carbamoyl]ethyl}piperidin-4-yl ester; -   biphenyl-2-ylcarbamic acid     1-{2-[4-(4-carbamoylpiperidin-1-ylmethyl)-2-chloro-5-methoxyphenylcarbamoyl]ethyl}piperidin-4-yl     ester; -   biphenyl-2-ylcarbamic acid     1-{2-[4-(4-carbamoylpiperidin-1-ylmethyl)-3-methoxy     phenylcarbamoyl]ethyl}piperidin-4-yl ester; -   biphenyl-2-ylcarbamic acid     1-{2-[4-(4-carbamoyl-piperidin-1-ylmethyl)-3-hydroxy     phenylcarbamoyl]ethyl}piperidin-4-yl ester; -   biphenyl-2-ylcarbamic acid     1-(2-{[4-(4-carbamoylpiperidin-1-ylmethyl)phenyl]methylcarbamoyl}ethyl)piperidin-4-yl     ester; -   biphenyl-2-ylcarbarnic acid     1-{2-[4-(4-methylcarbamoylpiperidin-1-ylmethyl)phenylcarbamoyl]ethyl}piperidin-4-yl     ester; -   biphenyl-2-ylcarbamic acid     1-{2-[4-(4-ethylcarbamoylpiperidin-1-ylmethyl)phenylcarbamoyl]ethyl}piperidin-4-yl     ester; -   biphenyl-2-yl-carbamic acid     1-{2-[4-(4-propylcarbamoylpiperidin-1-ylmethyl)phenylcarbamoyl]ethyl}piperidin-4-yl     ester; -   biphenyl-2-yl-carbamic acid     1-{2-[4-(4-isopropylcarbamoylpiperidin-1-ylmethyl)phenylcarbamoyl]ethyl}piperidin-4-yl     ester; -   biphenyl-2-yl-carbamic acid     1-{2-[4-(4-carbamoylpiperidin-1-ylmethyl)-2-chlorophenylcarbamoyl]ethyl}piperidin-4-yl     ester; and -   biphenyl-2-yl-carbamic acid     1-{2-[5-(4-carbamoylpiperidin-1-ylmethyl)thiophen-2-ylcarbamoyl]ethyl}piperidin-4-yl     ester;     or a pharmaceutically acceptable salt or solvate thereof

DEFINITIONS

When describing the compounds, compositions, methods and processes of this invention, the following terms have the following meanings unless otherwise indicated.

The term “alkyl” means a monovalent saturated hydrocarbon group which may be linear or branched. Unless otherwise defined, such alkyl groups typically contain from 1 to 10 carbon atoms. Representative alkyl groups include, by way of example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl and the like.

The term “alkylene” means a divalent saturated hydrocarbon group which may be linear or branched. Unless otherwise defined, such alkylene groups typically contain from 1 to 10 carbon atoms. Representative alkylene groups include, by way of example, methylene, ethane-1,2-diyl (“ethylene”), propane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl and the like.

The term “alkoxy” means a monovalent group of the formula (alkyl)-O—, where alkyl is as defined herein. Representative alkoxy groups include, by way of example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy and the like.

The term “alkenyl” means a monovalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon double bonds. Unless otherwise defined, such alkenyl groups typically contain from 2 to 10 carbon atoms. Representative alkenyl groups include, by way of example, ethenyl, n-propenyl, isopropenyl, n-but-2-enyl, n-hex-3-enyl and the like. The term “alkenylene” means a divalent alkenyl group.

The term “alkynyl” means a monovalent unsaturated hydrocarbon group which may be linear or branched and which has at least one, and typically 1, 2 or 3, carbon-carbon triple bonds. Unless otherwise defined, such alkynyl groups typically contain from 2 to 10 carbon atoms. Representative alkynyl groups include, by way of example, ethynyl, n-propynyl, n-but-2-ynyl, n-hex-3-ynyl and the like. The term “alkynylene” means a divalent alkynyl group.

The term “aryl” means a monovalent aromatic hydrocarbon having a single ring (i.e., phenyl) or fused rings (i.e., naphthalene). Unless otherwise defined, such aryl groups typically contain from 6 to 10 carbon ring atoms. Representative aryl groups include, by way of example, phenyl and naphthalene-1-yl, naphthalene-2-yl, and the like. The term “arylene” means a divalent aryl group.

The term “azacycloalkyl” means a monovalent heterocyclic ring containing one nitrogen atom, i.e., a cycloalkyl group in which one carbon atom has been replaced with a nitrogen atom. Unless otherwise defined, such azacycloalkyl groups typically contain from 2 to 9 carbon atoms. Representative examples of an azacycloalkyl group are pyrrolidinyl and piperidinyl groups. The term “azacycloalkylene” means a divalent azacycloakyl group. Representative examples of an azacycloalkylene group are pyrrolidinylene and piperidinylene groups.

The term “cycloalkyl” means a monovalent saturated carbocyclic hydrocarbon group. Unless otherwise defined, such cycloalkyl groups typically contain from 3 to 10 carbon atoms. Representative cycloalkyl groups include, by way of example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like. The term “cycloalkylene” means a divalent cycloalkyl group.

The term “halo” means fluoro, chloro, bromo and iodo.

The term “heteroaryl” means a monovalent aromatic group having a single ring or two fused rings and containing in the ring at least one heteroatom (typically 1 to 3 heteroatoms) selected from nitrogen, oxygen or sulfur. Unless otherwise defined, such heteroaryl groups typically contain from 5 to 10 total ring atoms. Representative heteroaryl groups include, by way of example, monovalent species of pyrrole, imidazole, thiazole, oxazole, furan, thiophene, triazole, pyrazole, isoxazole, isothiazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, indole, benzofuran, benzothiophene, benzimidazole, benzthiazole, quinoline, isoquinoline, quinazoline, quinoxaline and the like, where the point of attachment is at any available carbon or nitrogen ring atom. The term “heteroarylene” means a divalent heteroaryl group.

The term “heterocyclyl” or “heterocyclic” means a monovalent saturated or unsaturated (non-aromatic) group having a single ring or multiple condensed rings and containing in the ring at least one heteroatom (typically 1 to 3 heteroatoms) selected from nitrogen, oxygen or sulfur. Unless otherwise defined, such heterocyclic groups typically contain from 2 to 9 total ring carbon atoms. Representative heterocyclic groups include, by way of example, monovalent species of pyrrolidine, imidazolidine, pyrazolidine, piperidine, 1,4-dioxane, morpholine, thiomorpholine, piperazine, 3-pyrroline and the like, where the point of attachment is at any available carbon or nitrogen ring atom. The term “heterocyclene” means a divalent heterocyclyl or heterocyclic group.

When a specific number of carbon atoms is intended for a particular term used herein, the number of carbon atoms is shown in parentheses preceding the term. For example, the term “(1-4C)alkyl” means an alkyl group having from 1 to 4 carbon atoms.

The term “pharmaceutically acceptable salt” means a salt which is acceptable for administration to a patient, such as a mammal (e.g., salts having acceptable mammalian safety for a given dosage regime). Such salts can be derived from pharmaceutically acceptable inorganic or organic bases and from pharmaceutically acceptable inorganic or organic acids. Salts derived from pharmaceutically acceptable inorganic bases include ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic, manganous, potassium, sodium, zinc and the like. Particularly preferred are ammonium, calcium, magnesium, potassium and sodium salts. Salts derived from pharmaceutically acceptable organic bases include salts of primary, secondary and tertiary amines, including substituted amines, cyclic amines, naturally-occurring amines and the like, such as arginine, betaine, caffeine, choline, N,N′-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperadine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine and the like. Salts derived from pharmaceutically acceptable acids include acetic, ascorbic, benzenesulfonic, benzoic, camphosulfonic, citric, ethanesulfonic, edisylic, fumaric, gentisic, gluconic, glucoronic, glutamic, hippuric, hydrobromic, hydrochloric, isethionic, lactic, lactobionic, maleic, malic, mandelic, methanesulfonic, mucic, naphthalenesulfonic, naphthalene-1,5-disulfonic, naphthalene-2,6-disulfonic, nicotinic, nitric, orotic, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic, xinafoic and the like. Particularly preferred are citric, hydrobromic, hydrochloric, isethionic, maleic, naphthalene-1,5-disulfonic, phosphoric, sulfuric and tartaric acids.

The term “salt thereof” means a compound formed when the hydrogen of an acid is replaced by a cation, such as a metal cation or an organic cation and the like. Preferably, the salt is a pharmaceutically acceptable salt, although this is not required for salts of intermediate compounds that are not intended for administration to a patient.

The term “solvate” means a complex or aggregate formed by one or more molecules of a solute, i.e. a compound of formula I or a pharmaceutically acceptable salt thereof, and one or more molecules of a solvent. Such solvates are typically crystalline solids having a substantially fixed molar ratio of solute and solvent. Representative solvents include, by way of example, water, methanol, ethanol, isopropanol, acetic acid and the like. When the solvent is water, the solvate formed is a hydrate.

It will be appreciated that the term “or a pharmaceutically acceptable salt or solvate or stereoisomer thereof” is intended to include all permutations of salts, solvates and stereoisomers, such as a solvate of a pharmaceutically acceptable salt of a stereoisomer of a compound of formula I.

The term “therapeutically effective amount” means an amount sufficient to effect treatment when administered to a patient in need of treatment.

The term “treating” or “treatment” as used herein means the treating or treatment of a disease or medical condition (such as COPD) in a patient, such as a mammal (particularly a human) that includes:

-   -   (a) preventing the disease or medical condition from occurring,         i.e., prophylactic treatment of a patient;     -   (b) ameliorating the disease or medical condition, i.e.,         eliminating or causing regression of the disease or medical         condition in a patient;     -   (c) suppressing the disease or medical condition, i.e., slowing         or arresting the development of the disease or medical condition         in a patient; or     -   (d) alleviating the symptoms of the disease or medical condition         in a patient.

The term “leaving group” means a functional group or atom which can be displaced by another functional group or atom in a substitution reaction, such as a nucleophilic substitution reaction. By way of example, representative leaving groups include chloro, bromo and iodo groups; sulfonic ester groups, such as mesylate, tosylate, brosylate, nosylate and the like; and acyloxy groups, such as acetoxy, trifluoroacetoxy and the like.

The term “protected derivatives thereof” means a derivative of the specified compound in which one or more functional groups of the compound are protected from undesired reactions with a protecting or blocking group. Functional groups which may be protected include, by way of example, carboxylic acid groups, amino groups, hydroxyl groups, thiol groups, carbonyl groups and the like. Representative protecting groups for carboxylic acids include esters (such as a p-methoxybenzyl ester), amides and hydrazides; for amino groups, carbamates (such as tert-butoxycarbonyl) and amides; for hydroxyl groups, ethers and esters; for thiol groups, thioethers and thioesters; for carbonyl groups, acetals and ketals; and the like. Such protecting groups are well-known to those skilled in the art and are described, for example, in T. W. Greene and G. M. Wuts, Protecting Groups in Organic Synthesis, Third Edition, Wiley, New York, 1999, and references cited therein.

The term “amino-protecting group” means a protecting group suitable for preventing undesired reactions at an amino group. Representative amino-protecting groups include, but are not limited to, tert-butoxycarbonyl (BOC), trityl (Tr), benzyloxycarbonyl (Cbz), 9-fluorenylmethoxycarbonyl (Fmoc), formyl, trimethylsilyl (TMS), tert-butyldimethylsilyl (TBS), and the like.

The term “carboxy-protecting group” means a protecting group suitable for preventing undesired reactions at a carboxy group. Representative carboxy-protecting groups include, but are not limited to, esters, such as methyl, ethyl, tert-butyl, benzyl (Bn), p-methoxybenzyl (PMB), 9-fluroenylmethyl (Fm), trimethylsilyl (TMS), tert-butyldimethylsilyl (TBS), diphenylmethyl (benzhydryl, DPM) and the like.

The term “hydroxyl-protecting group” means a protecting group suitable for preventing undesirable reactions at a hydroxyl group. Representative hydroxyl-protecting groups include, but are not limited to, silyl groups including tri(1-6C)alkylsilyl groups, such as trimethylsilyl (TMS), triethylsilyl (TES), tert-butyldimethylsilyl (TBS) and the like; esters (acyl groups) including (1-6C)alkanoyl groups, such as formyl, acetyl and the like; arylmethyl groups, such as benzyl (Bn), p-methoxybenzyl (PMB), 9-fluorenylmethyl (Fm), diphenylmethyl (benzhydryl, DPM) and the like. Additionally, two hydroxyl groups can also be protected as an alkylidene group, such as prop-2-ylidine, formed, for example, by reaction with a ketone, such as acetone.

General Synthetic Procedures

The biphenyl compounds of this invention can be prepared from readily available starting materials using the following general methods and procedures or by using other information readily available to those of ordinary skill in the art. Although a particular embodiment of the present invention may be shown or described herein, those skilled in the art will recognize that all embodiments or aspects of the present invention can be prepared using the methods described herein or by using other methods, reagents and starting materials known to those skilled in the art. It will also be appreciated that where typical or preferred process conditions (i.e., reaction temperatures, times, mole ratios of reactants, solvents, pressures, etc.) are given, other process conditions can also be used unless otherwise stated. While the optimum reaction conditions may vary depending on the particular reactants or solvent used, such conditions can be readily determined by one skilled in the art by routine optimization procedures.

Additionally, as will be apparent to those skilled in the art, conventional protecting groups may be necessary or desired to prevent certain functional groups from undergoing undesired reactions. The choice of a suitable protecting group for a particular functional group as well as suitable conditions for protection and deprotection of such functional groups are well-known in the art. Protecting groups other than those illustrated in the procedures described herein may be used, if desired. For example, numerous protecting groups, and their introduction and removal, are described in T. W. Greene and G. M. Wuts, Protecting Groups in Organic Synthesis, Third Edition, Wiley, New York, 1999, and references cited therein.

By way of illustration, the compounds of formula I can be prepared by a process comprising:

(a) reacting a compound of formula II:

or a salt thereof, with a compound of formula III:

wherein Z¹ represents a leaving group;

(b) coupling a compound of formula IV:

or a reactive derivative thereof; with a compound of formula V:

(c) reacting a compound of formula VI:

wherein Z² represents a leaving group; with a compound of formula VII:

(d) reacting a compound of formula II with a compound of formula VIII:

in the presence of a reducing agent;

(e) reacting a compound of formula IX:

with a compound of formula VII in the presence of a reducing agent; or

(f) for a compound of formula I in which m is 0, reacting a compound of formula II with a compound of formula X:

and then removing any protecting groups that may be present to provide a compound of formula I; and optionally, forming a pharmaceutically acceptable salt thereof.

Generally, if a salt of one of the starting materials is used in the processes described above, such as an acid addition salt, the salt is typically neutralized before or during the reaction process. This neutralization reaction is typically accomplished by contacting the salt with one molar equivalent of a base for each molar equivalent of acid addition salt.

In process (a), the reaction between the compounds of formula II and III, the leaving represented by Z¹ can be, for example, halo, such as chloro, bromo or iodo, or a sulfonic ester group, such as mesylate or tosylate. The reaction is conveniently performed in the presence of a base, for example, a tertiary amine such as diisopropylethylamine. Convenient solvents include nitriles, such as acetonitrile. The reaction is conveniently conducted at a temperature in the range of from 0° C. to 100° C.

Compounds of formula II are generally known in the art, or can be prepared by deprotecting a compound of formula XI:

wherein P¹ represents an amino-protecting group, such as a benzyl group. Benzyl groups are conveniently removed by reduction, using a hydrogen or ammonium formate and a Group VIII metal catalyst, such as palladium. When W represents NW^(a), the hydrogenation is conveniently performed using Pearlman's catalyst (Pd(OH)₂).

Compounds of formula XI can be prepared by reacting an isocyanate compound of formula XII:

with a compound of formula XIII:

Compounds of formula III can be prepared starting from a corresponding compound in which Z¹ represents a hydroxyl group, for example, by reaction of a halogenating agent, such as thionyl chloride, to afford a compound of formula III in which Z¹ represents halo, such as chloro. Compounds in which Z¹ represents a hydroxyl group may be prepared, for example, by reacting a compound of formula V with an appropriate lactone, such as γ-butyrolactone.

In process (b), a compound of formula IV or reactive derivative thereof is reacted with a compound of formula V. By “reactive derivative” of compound IV, it is meant that the carboxylic acid is activated, for example, by forming an anhydride or carboxylic acid halide, such as a carboxylic acid chloride. Alternatively, the carboxylic acid can be activated using conventional carboxylic acid/amine coupling reagents, such carbodiimides, O-(7-azabenzotriazol-1-yl-N,N,N′,N′ tetramethyluronium hexafluorophosphate (HATU) and the like. This reaction is conveniently performed under conventional amide bond-forming conditions. The process is conveniently conducted at a temperature in the range of from −10° C. to 100° C.

Compounds of formula IV can be prepared by reacting a compound of formula II with a compound of formula XIV: Z³—CH₂(CH₂)_(m)CH₂COOP²  XIV wherein Z³ represents a leaving group including, for example, halo, such as chloro, bromo or iodo, or a sulfonic ester group, such as mesylate or tosylate; and P² represents a hydrogen atom or a carboxyl-protecting group, such as a (1-4C)alkyl group. If necessary, the carboxyl-protecting group P², is then removed, for example, by hydrolysis under conventional conditions, such as by using lithium hydroxide. Alternatively, when m is 0, compounds of formula IV can be prepared by reacting II with CH₂═CHC(O)OP² and then removing the carboxyl-protecting group P², if necessary.

Compounds of formula V can be prepared by reacting a compound of formula VII with a compound of formula XV:

wherein P³ represents hydrogen or an amino-protecting group, such as tert-butoxycarbonyl, and Z⁴ represents a leaving group including, for example, halo, such as chloro, bromo or iodo, or a sulfonic ester group, such as mesylate or tosylate; followed if necessary, by removing an amino-protecting group P³. Alternatively, such compounds can be prepared by reductive amination of a compound of formula XVI:

using a compound of formula VII under conventional reaction conditions, such as those described for processes (d) and (e).

Referring to process (c), the leaving group represented by Z² can be, for example, halo, such as chloro, bromo or iodo, or a sulfonic ester group, such as mesylate or tosylate. This reaction is conveniently performed in the presence of a base, for example, a tertiary amine such as diisopropylethylamine. Convenient solvents include nitriles, such as acetonitrile. The reaction is conveniently conducted at a temperature in the range of from 0° C. to 100° C.

The compounds of formula VI can be prepared by reacting a compound of formula IV with a compound of formula XVII:

This reaction is conveniently performed following, for example, the method of process (b) described herein.

In process (d), the reducing agent may be, for example, hydrogen in the presence of a Group VIII metal catalyst, such as palladium, or a metal hydride reducing agent, such as a borohydride, including sodium triacetoxyborohydride. Convenient solvents include alcohols, such as methanol. The reaction is conveniently performed at a temperature in the range of from 0° C. to 100° C.

The compounds of formula VIII may be prepared by oxidizing a compound corresponding to formula III in which Z¹ represents a hydroxyl group. Such oxidation reactions can be conducted, for example, using sulfur dioxide pyridine complex in dimethylsulfoxide in the presence of a tertiary amine, such as diisopropylethylamine.

In process (e), the reducing agent may be, for example, hydrogen in the presence of a Group VIII metal catalyst, such as palladium, or a metal hydride reducing agent including borohydrides, such as sodium triacetoxyborohydride, optionally used in combination with a titanium tetraalkoxide, such as titanium tetraisopropoxide. Convenient solvents include alcohols, such as methanol and halogenated hydrocarbons, such as dichloromethane. The reaction is conveniently performed at a temperature in the range of from 0° C. to 100° C.

Compounds of formula IX may be prepared by oxidizing a compound of XVIII:

using, for example, sulfur trioxide pyridine complex as an oxidizing agent.

Compounds of formula XVIII may be prepared by reacting a compound of formula IV with a compound of formula XIX:

following a method analogous to process step (b) described hereinabove.

In process (f), the reaction is typically conducted by contacting II with X in an inert diluent, such as dichloromethane, at a temperature of from about 20° C. to about 100° C. for about 6 to 48 hours or until the reaction is complete.

Compounds of formula X can be prepared by coupling a compound of formula XX:

with acrylic acid under conventional amide bond forming conditions.

As will be apparent to those skilled in the art, compounds of formula I prepared by any of steps (a) to (f) herein may be further derivatized to form other compounds of formula I using methods and reagents well-known in the art. By way of illustration, a compound of formula I may be reacted with bromine to afford a corresponding compound of formula I in which R², for example, represents a bromo group. Additionally, a compound of formula I in which R⁴ represents a hydrogen atom may be alkylated to afford a corresponding compound of formula I in which R⁴ represents a (1-4C) alkyl group.

Certain of the intermediates described herein are believed to be novel and accordingly, such compounds are provided as further aspects of the invention including, for example, the compounds of formula III, V and VIII and salts thereof.

Further details regarding specific reaction conditions and other procedures for preparing representative compounds of this invention or intermediates thereof are described in the Examples set forth below.

Pharmaceutical Compositions and Formulations

The biphenyl compounds of this invention are typically administered to a patient in the form of a pharmaceutical composition or formulation. Such pharmaceutical compositions may be administered to the patient by any acceptable route of administration including, but not limited to, inhaled, oral, nasal, topical (including transdermal) and parenteral modes of administration.

It will be understood that any form of the compounds of this invention, (i.e., free base, pharmaceutically acceptable salt, solvate, etc.) that is suitable for the particular mode of administration can be used in the pharmaceutical compositions discussed herein.

Accordingly, in one of its composition aspects, this invention is directed to a pharmaceutical composition comprising a pharmaceutically acceptable carrier or excipient and a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable salt or solvate or stereoisomer thereof. Optionally, such pharmaceutical compositions may contain other therapeutic and/or formulating agents if desired.

The pharmaceutical compositions of this invention typically contain a therapeutically effective amount of a compound of the present invention or a pharmaceutically acceptable salt or solvate or stereoisomer thereof. Typically, such pharmaceutical compositions will contain from about 0.01 to about 95% by weight of the active agent; including, from about 0.01 to about 30% by weight; such as from about 0.01 to about 10% by weight of the active agent.

Any conventional carrier or excipient may be used in the pharmaceutical compositions of this invention: The choice of a particular carrier or excipient, or combinations of carriers or excipients, will depend on the mode of administration being used to treat a particular patient or type of medical condition or disease state. In this regard, the preparation of a suitable pharmaceutical composition for a particular mode of administration is well within the scope of those skilled in the pharmaceutical arts. Additionally, the ingredients for such compositions are commercially available from, for example, Sigma, P.O. Box 14508, St. Louis, Mo. 63178. By way of further illustration, conventional formulation techniques are described in Remington: The Science and Practice of Pharmacy, 20^(th) Edition, Lippincott Williams & White, Baltimore, Md. (2000); and H. C. Ansel et al., Pharmaceutical Dosage Forms and Drug Delivery Systems, 7^(th) Edition, Lippincott Williams & White, Baltimore, Md. (1999).

Representative examples of materials which can serve as pharmaceutically acceptable carriers include, but are not limited to, the following: (1) sugars, such as lactose, glucose and sucrose; (2) starches, such as corn starch and potato starch; (3) cellulose, and its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; (4) powdered tragacanth; (5) malt; (6) gelatin; (7) talc; (8) excipients, such as cocoa butter and suppository waxes; (9) oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; (10) glycols, such as propylene glycol; (11) polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; (12) esters, such as ethyl oleate and ethyl laurate; (13) agar; (14) buffering agents, such as magnesium hydroxide and aluminum hydroxide; (15) alginic acid; (16) pyrogen-free water; (17) isotonic saline; (18) Ringer's solution; (19) ethyl alcohol; (20) phosphate buffer solutions;

(21) compressed propellant gases, such as chlorofluorocarbons and hydrofluorocarbons; and (22) other non-toxic compatible substances employed in pharmaceutical compositions.

The pharmaceutical compositions of this invention are typically prepared by thoroughly and intimately mixing or blending a compound of the invention with a pharmaceutically acceptable carrier and one or more optional ingredients. If necessary or desired, the resulting uniformly blended mixture can then be shaped or loaded into tablets, capsules, pills, canisters, cartridges, dispensers and the like using conventional procedures and equipment.

In one embodiment, the pharmaceutical compositions of this invention are suitable for inhaled administration. Suitable pharmaceutical compositions for inhaled administration will typically be in the form of an aerosol or a powder. Such compositions are generally administered using well-known delivery devices, such as a nebulizer inhaler, a metered-dose inhaler (MDI), a dry powder inhaler (DPI) or a similar delivery device.

In a specific embodiment of this invention, the pharmaceutical composition comprising the active agent is administered by inhalation using a nebulizer inhaler. Such nebulizer devices typically produce a stream of high velocity air that causes the pharmaceutical composition comprising the active agent to spray as a mist that is carried into the patient's respiratory tract. Accordingly, when formulated for use in a nebulizer inhaler, the active agent is typically dissolved in a suitable carrier to form a solution. Alternatively, the active agent can be micronized and combined with a suitable carrier to form a suspension of micronized particles of respirable size, where micronized is typically defined as having about 90% or more of the particles with a diameter of less than about 10 μm. Suitable nebulizer devices are provided commercially, for example, by PARI GmbH (Starnberg, German). Other nebulizer devices include Respimat (Boehringer Ingelheim) and those disclosed, for example, in U.S. Pat. No. 6,123,068 to Lloyd et al. and WO 97/12687 (Eicher et al.).

A representative pharmaceutical composition for use in a nebulizer inhaler comprises an isotonic aqueous solution comprising from about 0.05 μg/mL to about 10 mg/mL of a compound of formula I or a pharmaceutically acceptable salt or solvate or stereoisomer thereof.

In another specific embodiment of this invention, the pharmaceutical composition comprising the active agent is administered by inhalation using a dry powder inhaler. Such dry powder inhalers typically administer the active agent as a free-flowing powder that is dispersed in a patient's air-stream during inspiration. In order to achieve a free flowing powder, the active agent is typically formulated with a suitable excipient such as lactose or starch.

A representative pharmaceutical composition for use in a dry powder inhaler comprises dry lactose having a particle size between about 1 μm and about 100 μm and micronized particles of a compound of formula I, or a pharmaceutically acceptable salt or solvate or stereoisomer thereof.

Such a dry powder formulation can be made, for example, by combining the lactose with the active agent and then dry blending the components. Alternatively, if desired, the active agent can be formulated without an excipient. The pharmaceutical composition is then typically loaded into a dry powder dispenser, or into inhalation cartridges or capsules for use with a dry powder delivery device.

Examples of dry powder inhaler delivery devices include Diskhaler (GlaxoSmithKline, Research Triangle Park, N.C.) (see, e.g., U.S. Pat. No. 5,035,237 to Newell et al.); Diskus (GlaxoSmithKline) (see, e.g., U.S. Pat. No. 6,378,519 to Davies et al.); Turbuhaler (AstraZeneca, Wilmington, Del.) (see, e.g., U.S. Pat. No. 4,524,769 to Wetterlin); Rotahaler (GlaxoSmithKline) (see, e.g., U.S. Pat. No. 4,353,365 to Hallworth et al.) and Handihaler (Boehringer Ingelheim). Further examples of suitable DPI devices are described in U.S. Pat. No. 5,415,162 to Casper et al., U.S. Pat. No. 5,239,993 to Evans, and U.S. Pat. No. 5,715,810 to Armstrong et al., and references cited therein.

In yet another specific embodiment of this invention, the pharmaceutical composition comprising the active agent is administered by inhalation using a metered-dose inhaler. Such metered-dose inhalers typically discharge a measured amount of the active agent or a pharmaceutically acceptable salt or solvate or stereoisomer thereof using compressed propellant gas. Accordingly, pharmaceutical compositions administered using a metered-dose inhaler typically comprise a solution or suspension of the active agent in a liquefied propellant. Any suitable liquefied propellant may be employed including chlorofluorocarbons, such as CCl₃F, and hydrofluoroalkanes (HFAs), such as 1,1,1,2-tetrafluoroethane (HFA 134a) and 1,1,1,2,3,3,3-heptafluoro-n-propane, (HFA 227). Due to concerns about chlorofluorocarbons affecting the ozone layer, formulations containing HFAs are generally preferred. Additional optional components of HFA formulations include co-solvents, such as ethanol or pentane, and surfactants, such as sorbitan trioleate, oleic acid, lecithin, and glycerin. See, for example, U.S. Pat. No. 5,225,183 to Purewal et al., EP 0717987 A2 (Minnesota Mining and Manufacturing Company), and WO 92/22286 (Minnesota Mining and Manufacturing Company).

A representative pharmaceutical composition for use in a metered-dose inhaler comprises from about 0.01% to about 5% by weight of a compound of formula I, or a pharmaceutically acceptable salt or solvate or stereoisomer thereof; from about 0% to about 20% by weight ethanol; and from about 0% to about 5% by weight surfactant; with the remainder being an HFA propellant.

Such compositions are typically prepared by adding chilled or pressurized hydrofluoroalkane to a suitable container containing the active agent, ethanol (if present) and the surfactant (if present). To prepare a suspension, the active agent is micronized and then combined with the propellant. The formulation is then loaded into an aerosol canister, which forms a portion of a metered-dose inhaler device. Examples of metered-dose inhaler devices developed specifically for use with HFA propellants are provided in U.S. Pat. No. 6,006,745 to Marecki and U.S. Pat. No. 6,143,277 to Ashurst et al. Alternatively, a suspension formulation can be prepared by spray drying a coating of surfactant on micronized particles of the active agent. See, for example, WO 99/53901 (Glaxo Group Ltd.) and WO 00/61108 (Glaxo Group Ltd.).

For additional examples of processes of preparing respirable particles, and formulations and devices suitable for inhalation dosing see U.S. Pat. No. 6,268,533 to Gao et al., U.S. Pat. No. 5,983,956 to Trofast, U.S. Pat. No. 5,874,063 to Briggner et al., and U.S. Pat. No. 6,221,398 to Jakupovic et al.; and WO 99/55319 (Glaxo Group Ltd.) and WO 00/30614 (AstraZeneca AB).

In another embodiment, the pharmaceutical compositions of this invention are suitable for oral administration. Suitable pharmaceutical compositions for oral administration may be in the form of capsules, tablets, pills, lozenges, cachets, dragees, powders, granules; or as a solution or a suspension in an aqueous or non-aqueous liquid; or as an oil-in-water or water-in-oil liquid emulsion; or as an elixir or syrup; and the like; each containing a predetermined amount of a compound of the present invention as an active ingredient.

When intended for oral administration in a solid dosage form (i.e., as capsules, tablets, pills and the like), the pharmaceutical compositions of this invention will typically comprise a compound of the present invention as the active ingredient and one or more pharmaceutically acceptable carriers, such as sodium citrate or dicalcium phosphate. Optionally or alternatively, such solid dosage forms may also comprise: (1) fillers or extenders, such as starches, lactose, sucrose, glucose, mannitol, and/or silicic acid; (2) binders, such as carboxymethylcellulose, alginates, gelatin, polyvinyl pyrrolidone, sucrose and/or acacia; (3) humectants, such as glycerol; (4) disintegrating agents, such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and/or sodium carbonate; (5) solution retarding agents, such as paraffin; (6) absorption accelerators, such as quaternary ammonium compounds; (7) wetting agents, such as cetyl alcohol and/or glycerol monostearate; (8) absorbents, such as kaolin and/or bentonite clay; (9) lubricants, such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and/or mixtures thereof; (10) coloring agents; and (11) buffering agents.

Release agents, wetting agents, coating agents, sweetening, flavoring and perfuming agents, preservatives and antioxidants can also be present in the pharmaceutical compositions of this invention. Examples of pharmaceutically acceptable antioxidants include: (1) water-soluble antioxidants, such as ascorbic acid, cysteine hydrochloride, sodium bisulfate, sodium metabisulfate sodium sulfite and the like; (2) oil-soluble antioxidants, such as ascorbyl palmitate, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), lecithin, propyl gallate, alpha-tocopherol, and the like; and (3) metal-chelating agents, such as citric acid, ethylencdiamine tetraacetic acid (EDTA), sorbitol, tartaric acid, phosphoric acid, and the like. Coating agents for tablets, capsules, pills and like, include those used for enteric coatings, such as cellulose acetate phthalate (CAP), polyvinyl acetate phthalate (PVAP), hydroxypropyl methylcellulose phthalate, methacrylic acid-methacrylic acid ester copolymers, cellulose acetate trimellitate (CAT), carboxymethyl ethyl cellulose (CMEC), hydroxypropyl methyl cellulose acetate succinate (HPMCAS), and the like.

If desired, the pharmaceutical compositions of the present invention may also be formulated to provide slow or controlled release of the active ingredient using, by way of example, hydroxypropyl methyl cellulose in varying proportions; or other polymer matrices, liposomes and/or microspheres.

In addition, the pharmaceutical compositions of the present invention may optionally contain opacifying agents and may be formulated so that they release the active ingredient only, or preferentially, in a certain portion of the gastrointestinal tract, optionally, in a delayed manner. Examples of embedding compositions which can be used include polymeric substances and waxes. The active ingredient can also be in micro-encapsulated form, if appropriate, with one or more of the above-described excipients.

Suitable liquid dosage forms for oral administration include, by way of illustration, pharmaceutically acceptable emulsions, microemulsions, solutions, suspensions, syrups and elixirs. Such liquid dosage forms typically comprise the active ingredient and an inert diluent, such as, for example, water or other solvents, solubilizing agents and emulsifiers, such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, oils (e.g., cottonseed, groundnut, corn, germ, olive, castor and sesame oils), glycerol, tetrahydrofuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof. Suspensions, in addition to the active ingredient, may contain suspending agents such as, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminium metahydroxide, bentonite, agar-agar and tragacanth, and mixtures thereof.

When intended for oral administration, the pharmaceutical compositions of this invention are preferably packaged in a unit dosage form. The term “unit dosage form” means a physically discrete unit suitable for dosing a patient, i.e., each unit containing a predetermined quantity of active agent calculated to produce the desired therapeutic effect either alone or in combination with one or more additional units. For example, such unit dosage forms may be capsules, tablets, pills, and the like.

The compounds of this invention can also be administered transdermally using known transdermal delivery systems and excipients. For example, a compound of this invention can be admixed with permeation enhancers, such as propylene glycol, polyethylene glycol monolaurate, azacycloalkan-2-ones and the like, and incorporated into a patch or similar delivery system. Additional excipients including gelling agents, emulsifiers and buffers, may be used in such transdermal compositions if desired.

The pharmaceutical compositions of this invention may also contain other therapeutic agents that are co-administered with a compound of formula I, or pharmaceutically acceptable salt or solvate or stereoisomer thereof. For example, the pharmaceutical compositions of this invention may further comprise one or more therapeutic agents selected from other bronchodilators (e.g., PDE₃ inhibitors, adenosine 2b modulators and β₂ adrenergic receptor agonists); anti-inflammatory agents (e.g., steroidal anti-inflammatory agents, such as corticosteroids; non-steroidal anti-inflammatory agents (NSAIDs), and PDE₄ inhibitors); other muscarinic receptor antagonists (i.e., antichlolinergic agents); antiinfective agents (e.g., Gram positive and Gram negative antibiotics or antivirals); antihistamines; protease inhibitors; and afferent blockers (e.g., D₂ agonists and neurokinin modulators). In one particular aspect of the invention, the compound of the invention is co-administered with a 13₂ adrenergic receptor agonist and a steroidal anti-inflammatory agent. The other therapeutic agents can be used in the form of pharmaceutically acceptable salts or solvates. Additionally, if appropriate, the other therapeutic agents can be used as optically pure stereoisomers.

Representative β₂ adrenergic receptor agonists that can be used in combination with the compounds of this invention include, but are not limited to, salmeterol, salbutamol, formoterol, salmefamol, fenoterol, terbutaline, albuterol, isoetharine, metaproterenol, bitolterol, pirbuterol, levalbuterol and the like, or pharmaceutically acceptable salts thereof. Other β₂ adrenergic receptor agonists that can be used in combination with the compounds of this invention include, but are not limited to, 3-(4-{[6-({(2R)-2-hydroxy-2-[4-hydroxy-3-(hydroxymethyl)-phenyl]ethyl}amino)-hexyl]oxy}butyl)benzenesulfonamide and 3-(-3-{[7-({(2R)-2-hydroxy-2-[4-hydroxy-3-(hydroxymethyl)phenyl]ethyl}-amino)heptyl]oxy}-propyl)benzenesulfonamide and related compounds disclosed in WO 02/066422 (Glaxo Group Ltd.); 3-[3-(4-{[6-([(2R)-2-hydroxy-2-[4-hydroxy-3-(hydroxymethyl)phenyl]ethyl}amino)hexyl]oxy}butyl)-phenyl]imidazolidine-2,4-dione and related compounds disclosed in WO 02/070490 (Glaxo Group Ltd.); 3-(4-{[6-({(2R)-2-[3-(formylamino)-4-hydroxyphenyl]-2-hydroxyethyl}amino)hexyl]oxy}butyl)-benzenesulfonamide, 3-(4-{[6-({(2S)-2-[3-(formylamino)-4-hydroxyphenyl]-2-hydroxyethyl}amino)hexyl]oxy}butyl)-benzenesulfonamide, 3-(4-{[6-({(2R/S)-2-[3-(formylamino)-4-hydroxyphenyl]-2-hydroxyethyl}amino)hexyl]oxy}butyl)-benzenesulfonamide, N-(tert-butyl)-3-(4-{[6-({(2R)-2-[3-(formylamino)-4-hydroxyphenyl]-2-hydroxyethyl}amino)hexyl]-oxy}butyl)benzenesulfonamide, N-(tert-butyl)-3-(4-{[6-({(2S)-2-[3-(formylamino)-4-hydroxyphenyl]-2-hydroxyethyl}amino)-hexyl]oxy}butyl)-benzenesulfonamide, N-(tert-butyl)-3-(4-{[6-({(2R/S)-2-[3-(formylamino)-4-hydroxyphenyl]-2-hydroxyethyl}amino)hexyl]-oxy}butyl)benzenesulfonamide and related compounds disclosed in WO 02/076933 (Glaxo Group Ltd.); 4-{(1R)-2-[(6-{2-[(2,6-dichlorobenzypoxy]ethoxy}hexyl)amino]-1-hydroxyethyl}-2-(hydroxymethyl)phenol and related compounds disclosed in WO 03/024439 (Glaxo Group Ltd.); N-{2-[4-((R)-2-hydroxy-2-phenylethylamino)phenyl]ethyl}-(R)-2-hydroxy-2-(3-formamido-4-hydroxyphenyl)ethylamine and related compounds disclosed in U.S. Pat. No. 6,576,793 to Moran et al.; N-{2-[4-(3-phenyl-4-methoxyphenyl)aminophenyl]ethyl}-(R)-2-hydroxy-2-(8-hydroxy-2(1H)-quinolinon-5-yl)ethylamine and related compounds disclosed in U.S. Pat. No. 6,653,323 to Moran et al.; and pharmaceutically acceptable salts thereof. In a particular embodiment, the β₂-adrenoreceptor agonist is a crystalline monohydrochloride salt of N-{2-[4-((R)-2-hydroxy-2-phenylethylamino)phenyl]ethyl}-(R)-2-hydroxy-2-(3-formamido-4-hydroxyphenyl)ethylamine. When employed, the β₂-adrenoreceptor agonist will be present in the pharmaceutical composition in a therapeutically effective amount. Typically, the β₂-adrenoreceptor agonist will be present in an amount sufficient to provide from about 0.05 μg to about 500 μg per dose.

Representative steroidal anti-inflammatory agents that can be used in combination with the compounds of this invention include, but are not limited to, methyl prednisolone, prednisolone, dexamethasone, fluticasone propionate, 6α,9α-difluoro-17α-[(2-furanyl carbonyl)oxy]-11β-hydroxy-16α-methyl-3-oxoandrosta-1,4-diene-17β-carbothioic acid S-fluoromethyl ester, 6α,9α-difluoro-11β-hydroxy-16α-methyl-3-oxo-17α-propionyloxy-androsta-1,4-diene-17β-carbothioic acid S-(2-oxo-tetrahydrofuran-3S-yl)ester, beclomethasone esters (e.g., the 17-propionate ester or the 17,21-dipropionate ester), budesonide, flunisolide, mometasone esters (e.g., the furoate ester), triamcinolone acetonide, rofleponide, ciclesonide, butixocort propionate, RPR-106541, ST-126 and the like, or pharmaceutically-acceptable salts thereof. When employed, the steroidal anti-inflammatory agent will be present in the pharmaceutical composition in a therapeutically effective amount. Typically, the steroidal anti-inflammatory agent will be present in an amount sufficient to provide from about 0.05 μg to about 500 μg per dose.

An exemplary combination is a compound of formula I, or pharmaceutically acceptable salt or solvate or stereoisomer thereof, co-administered with salmeterol as the β₂ adrenergic receptor agonist, and fluticasone propionate as the steroidal anti-inflammatory agent. Another exemplary combination is a compound of formula I, or pharmaceutically acceptable salt or solvate or stereoisomer thereof, co-administered with a crystalline monohydrochloride salt of N-{2-[4-((R)-2-hydroxy-2-phenylethylamino)phenyl]ethyl}-(R)-2-hydroxy-2-(3-formamido-4-hydroxyphenyl)ethylamine as the β₂-adrenoreceptor agonist, and 6α,9α-difluoro-17α-[(2-furanylcarbonyl)oxy]-11β-hydroxy-16α-methyl-3-oxoandrosta-1,4-diene-17β-carbothioic acid S-fluoromethyl ester as the steroidal anti-inflammatory agent.

Other suitable combinations include, for example, other anti-inflammatory agents, e.g., NSAIDs (such as sodium cromoglycate; nedocromil sodium; phosphodiesterase (PDE) inhibitors (e.g., theophylline, PDE4 inhibitors or mixed PDE3/PDE4 inhibitors); leukotriene antagonists (e.g., monteleukast); inhibitors of leukotriene synthesis; iNOS inhibitors; protease inhibitors, such as tryptase and elastase inhibitors; beta-2 integrin antagonists and adenosine receptor agonists or antagonists (e.g., adenosine 2a agonists); cytokine antagonists (e.g., chemokine antagonists such as, an interleukin antibody (αIL antibody), specifically, an αIL-4 therapy, an αIL-13 therapy, or a combination thereof); or inhibitors of cytokine synthesis.

For example, representative phosphodiesterase-4 (PDE4) inhibitors or mixed PDE3/PDE4 inhibitors that can be used in combination with the compounds of this invention include, but are not limited to cis 4-cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)cyclohexan-1-carboxylic acid, 2-carbomethoxy-4-cyano-4-(3-cyclopropylmethoxy-4-difluoromethoxyphenyl)cyclohexan-1-one; cis-[4-cyano-4-(3-cyclopropylmethoxy-4-difluoromethoxyphenyl)cyclohexan-1-ol]; cis-4-cyano-4-[3-(cyclopentyloxy)-4-methoxyphenyl]cyclohexane-1-carboxylic acid and the like, or pharmaceutically acceptable salts thereof. Other representative PDE4 or mixed PDE4/PDE3 inhibitors include AWD-12-281 (elbion); NCS-613 (INSERM); D-4418 (Chiroscience and Schering-Plough); CI-1018 or PD-168787 (Pfizer); benzodioxole compounds disclosed in WO99/16766 (Kyowa Hakko); K-34 (Kyowa Hakko); V-11294A (Napp); roflumilast (Byk-Gulden); pthalazinone compounds disclosed in WO99/47505 (Byk-Gulden); Pumafentrine (Byk-Gulden, now Altana); arofylline (Almirall-Prodesfarma); VM554/LTM565 (Vernalis); T-440 (Tanabe Seiyaku); and T2585 (Tanabe Seiyaku).

Representative muscarinic antagonists (i.e., anticholinergic agents) that can be used in combination with, and in addition to, the compounds of this invention include, but are not limited to, atropine, atropine sulfate, atropine oxide, methylatropine nitrate, homatropine hydrobromide, hyoscyamine(d,l)hydrobromide, scopolamine hydrobromide, ipratropium bromide, oxitropium bromide, tiotropium bromide, methantheline, propantheline bromide, anisotropine methyl bromide, clidinium bromide, copyrrolate (Robinul), isopropamide iodide, mepenzolate bromide, tridihexethyl chloride (Pathilone), hexocyclium methylsulfate, cyclopentolate hydrochloride, tropicamide, trihexyphenidyl hydrochloride, pirenzepine, telenzepine, AF-DX 116 and methoctramine and the like, or a pharmaceutically acceptable salt thereof; or, for those compounds listed as a salt, alternate pharmaceutically acceptable salt thereof.

Representative antihistamines (i.e., H₁-receptor antagonists) that can be used in combination with the compounds of this invention include, but are not limited to, ethanolamines, such as carbinoxamine maleate, clemastine fumarate, diphenylhydramine hydrochloride and dimenhydrinate; ethylenediamines, such as pyrilamine amleate, tripelennamine hydrochloride and tripelennamine citrate; alkylamines, such as chlorpheniramine and acrivastine; piperazines, such as hydroxyzine hydrochloride, hydroxyzine pamoate, cyclizine hydrochloride, cyclizine lactate, meclizine hydrochloride and cetirizine hydrochloride; piperidines, such as astemizole, levocabastine hydrochloride, loratadine or its descarboethoxy analogue, terfenadine and fexofenadine hydrochloride; azelastine hydrochloride; and the like, or a pharmaceutically acceptable salt thereof; or, for those compounds listed as a salt, alternate pharmaceutically acceptable salt thereof.

Suitable doses for the other therapeutic agents administered in combination with a compound of the invention are in the range of about 0.05 μg/day to about 100 mg/day.

The following formulations illustrate representative pharmaceutical compositions of the present invention:

Formulation Example A

A dry powder for administration by inhalation is prepared as follows:

Ingredients Amount Compound of the invention 0.2 mg Lactose  25 mg

Representative Procedure: The compound of the invention is micronized and then blended with lactose. This blended mixture is then loaded into a gelatin inhalation cartridge. The contents of the cartridge are administered using a powder inhaler.

Formulation Example B

A dry powder formulation for use in a dry powder inhalation device is prepared as follows:

Representative Procedure: A pharmaceutical composition is prepared having a bulk formulation ratio of micronized compound of the invention to lactose of 1:200. The composition is packed into a dry powder inhalation device capable of delivering between about 10 μg and about 100 μg of the compound of the invention per dose.

Formulation Example C

A dry powder for administration by inhalation in a metered dose inhaler is prepared as follows:

Representative Procedure: A suspension containing 5 wt % of a compound of the invention and 0.1 wt % lecithin is prepared by dispersing 10 g of the compound of the invention as micronized particles with mean size less than 10 μm in a solution formed from 0.2 g of lecithin dissolved in 200 mL of demineralized water. The suspension is spray dried and the resulting material is micronized to particles having a mean diameter less than 1.5 μm. The particles are loaded into cartridges with pressurized 1,1,1,2-tetrafluoroethane.

Formulation Example D

A pharmaceutical composition for use in a metered dose inhaler is prepared as follows:

Representative Procedure: A suspension containing 5 wt % compound of the invention, 0.5 wt % lecithin, and 0.5 wt % trehalose is prepared by dispersing 5 g of active ingredient as micronized particles with mean size less than 10 μm in a colloidal solution formed from 0.5 g of trehalose and 0.5 g of lecithin dissolved in 100 mL of demineralized water. The suspension is spray dried and the resulting material is micronized to particles having a mean diameter less than 1.5 μm. The particles are loaded into canisters with pressurized 1,1,1,2-tetrafluoroethane.

Formulation Example E

A pharmaceutical composition for use in a nebulizer inhaler is prepared as follows:

Representative Procedure: An aqueous aerosol formulation for use in a nebulizer is prepared by dissolving 0.1 mg of the compound of the invention in 1 mL of a 0.9% sodium chloride solution acidified with citric acid. The mixture is stirred and sonicated until the active ingredient is dissolved. The pH of the solution is adjusted to a value in the range of from 3 to 8 by the slow addition of NaOH.

Formulation Example F

Hard gelatin capsules for oral administration are prepared as follows:

Ingredients Amount Compound of the invention 250 mg Lactose (spray-dried) 200 mg Magnesium stearate  10 mg

Representative Procedure: The ingredients are thoroughly blended and then loaded into a hard gelatin capsule (460 mg of composition per capsule).

Formulation Example G

A suspension for oral administration is prepared as follows:

Ingredients Amount Compound of the invention 1.0 g Fumaric acid 0.5 g Sodium chloride 2.0 g Methyl paraben 0.15 g Propyl paraben 0.05 g Granulated sugar 25.5 g Sorbitol (70% solution) 12.85 g Veegum k (Vanderbilt Co.) 1.0 g Flavoring 0.035 mL Colorings 0.5 mg Distilled water q.s. to 100 mL

Representative Procedure: The ingredients are mixed to form a suspension containing 100 mg of active ingredient per 10 mL of suspension.

Formulation Example H

An injectable formulation is prepared as follows:

Ingredients Amount Compound of the invention 0.2 g Sodium acetate buffer solution (0.4 M)  2.0 mL HCl (0.5 N) or NaOH (0.5 N) q.s. to pH 4 Water (distilled, sterile) q.s. to 20 mL

Representative Procedure: The above ingredients are blended and the pH is adjusted to 4±0.5 using 0.5 N HCl or 0.5 N NaOH.

Utility

The biphenyl compounds of this invention are expected to be useful as muscarinic receptor antagonists and therefore, such compounds are expected to be useful for treating medical conditions mediated by muscarinic receptors, i.e., medical conditions which are ameliorated by treatment with a muscarinic receptor antagonist. Such medical conditions include, by way of example, pulmonary disorders or diseases including those associated with reversible airway obstruction, such as chronic obstructive pulmonary disease (e.g., chronic and wheezy bronchitis and emphysema), asthma, pulmonary fibrosis, allergic rhinitis, rhinorrhea, and the like. Other medical conditions that can be treated with muscarinic receptor antagonists are genitourinary tract disorders, such as overactive bladder or detrusor hyperactivity and their symptoms; gastrointestinal tract disorders, such as irritable bowel syndrome, diverticular disease, achalasia, gastrointestinal hypermotility disorders and diarrhea; cardiac arrhythmias, such as sinus bradycardia; Parkinson's disease; cognitive disorders, such as Alzheimer's disease; dismenorrhea; and the like.

In one embodiment, the compounds of this invention are useful for treating smooth muscle disorders in mammals, including humans and their companion animals (e.g., dogs, cats etc.). Such smooth muscle disorders include, by way of illustration, overactive bladder, chronic obstructive pulmonary disease and irritable bowel syndrome.

When used to treat smooth muscle disorders or other conditions mediated by muscarinic receptors, the compounds of this invention will typically be administered orally, rectally, parenterally or by inhalation in a single daily dose or in multiple doses per day. The amount of active agent administered per dose or the total amount administered per day will typically be determined by the patient's physician and will depend on such factors as the nature and severity of the patients condition, the condition being treated, the age and general health of the patient, the tolerance of the patient to the active agent, the route of administration and the like.

Typically, suitable doses for treating smooth muscle disorders or other disorders mediated by muscarinic receptors will range from about 0.14 μg/kg/day to about 7 mg/kg/day of active agent; including from about 0.15 μg/kg/day to about 5 mg/kg/day. For an average 70 kg human, this would amount to about 10 μg per day to about 500 mg per day of active agent.

In a specific embodiment, the compounds of this invention are useful for treating pulmonary or respiratory disorders, such as COPD or asthma, in mammals including humans. When used to treat such disorders, the compounds of this invention will typically be administered by inhalation in multiple doses per day, in a single daily dose or a single weekly dose. Generally, the dose for treating a pulmonary disorder will range from about 10 μg/day to about 200 μg/day. As used herein, COPD includes chronic obstructive bronchitis and emphysema (see, for example, Barnes, Chronic Obstructive Pulmonary Disease, N Engl J Med 343:269-78 (2000)).

When used to treat a pulmonary disorder, the compounds of this invention are optionally administered in combination with other therapeutic agents such as β₂-adrenoreceptor agonist; a corticosteroid, a non-steroidal anti-inflammatory agent, or combinations thereof.

When administered by inhalation, the compounds of this invention typically have the effect of producing bronchodilation. Accordingly, in another of its method aspects, this invention is directed to a method of producing bronchodilation in a patient, the method comprising administering to a patient a bronchodilation-producing amount of a compound of the invention. Generally, the therapeutically effective dose for producing bronchodilation will range from about 10 μg/day to about 200 μg/day.

In another embodiment, the compounds of this invention are used to treat overactive bladder. When used to treat overactive bladder, the compounds of this invention will typically be administered orally in a single daily dose or in multiple doses per day; preferably in a single daily dose. Preferably, the dose for treating overactive bladder will range from about 1.0 to about 500 mg/day.

In yet another embodiment, the compounds of this invention are used to treat irritable bowel syndrome. When used to treat irritable bowel syndrome, the compounds of this invention will typically be administered orally or rectally in a single daily dose or in multiple doses per day. Preferably, the dose for treating irritable bowel syndrome will range from about 1.0 to about 500 mg/day.

Since compounds of this invention are muscarinic receptor antagonists, such compounds are also useful as research tools for investigating or studying biological systems or samples having muscarinic receptors. Such biological systems or samples may comprise M₁, M₂, M₃, M₄ and/or M₅ muscarinic receptors. Any suitable biological system or sample having muscarinic receptors may be employed in such studies which may be conducted either in vitro or in vivo. Representative biological systems or samples suitable for such studies include, but are not limited to, cells, cellular extracts, plasma membranes, tissue samples, mammals (such as mice, rats, guinea pigs, rabbits, dogs, pigs, etc.), and the like.

In this embodiment, a biological system or sample comprising a muscarinic receptor is contacted with a muscarinic receptor-antagonizing amount of a compound of this invention. The effects of antagonizing the muscarinic receptor are then determined using conventional procedures and equipment, such as radioligand binding assays and functional assays. Such functional assays include ligand-mediated changes in intracellular cyclic adenosine monophosphate (cAMP), ligand-mediated changes in activity of the enzyme adenylyl cyclase (which synthesizes cAMP), ligand-mediated changes in incorporation of guanosine 5′-O-(γ-thio)triphosphate ([³⁵S]GTPγS) into isolated membranes via receptor catalyzed exchange of [³⁵S]GTPγS for GDP, ligand-mediated changes in free intracellular calcium ions (measured, for example, with a fluorescence-linked imaging plate reader or FLIPR® from Molecular Devices, Inc.). A compound of this invention will antagonize or decrease the activation of muscarinic receptors in any of the functional assays listed above, or assays of a similar nature. A muscarinic receptor-antagonizing amount of a compound of this invention will typically range from about about 0.1 nanomolar to about 100 nanomolar.

Additionally, the compounds of this invention can be used as research tools for discovering new compounds that have muscarinic receptor antagonist activity. In this embodiment, muscarinic receptor binding data (e.g., as determined by in vitro radioligand displacement assays) for a test compound or a group of test compounds is compared to the muscarinic receptor binding data for a compound of this invention to identify those test compounds that have about equal or superior muscarinic receptor binding, if any. This aspect of the invention includes, as separate embodiments, both the generation of comparison data (using the appropriate assays) and the analysis of the test data to identify test compounds of interest.

In another embodiment, the compounds of this invention are used to antagonize a muscarinic receptor in biological system, and a mammal in particular, such as mice, rats, guinea pigs, rabbits, dogs, pigs, humans and so forth. In this embodiment, a therapeutically effective amount of the compound of formula I is administered to the mammal. The effects of antagonizing the muscarinic receptor can then determined using conventional procedures and equipment, examples of which are described above.

Among other properties, compounds of this invention have been found to be potent inhibitors of M₃ muscarinic receptor activity. Accordingly, in a specific embodiment, this invention is directed to compounds of formula I having an inhibition dissociation constant (K_(i)) for the M₃ receptor subtype of less than or equal to 10 nM; preferably, less than or equal to 5 nM; (as determined, for example, by an in vitro radioligand displacement assay). Additionally, compounds of this invention are expected to possess a desirable duration of action. Accordingly, in another specific embodiment, this invention is directed to compounds of formula I having a duration of action greater than or equal to about 24 hours.

Moreover, compounds of this invention are also expected to possess reduced side effects, such as dry mouth, at efficacious doses when administered by inhalation compared to other known muscarinic receptor antagonists administered by inhalation (such as tiotropium).

These properties, as well as the utility of the compounds of this invention, can be demonstrated using various in vitro and in vivo assays well-known to those skilled in the art. For example, representative assays are described in further detail in the following Examples.

EXAMPLES

The following Preparations and Examples illustrate specific embodiments of this invention. In these examples, the following abbreviations have the following meanings:

-   -   AC adenylyl cyclase     -   ACh acetylcholine     -   ACN acetonitrile     -   BSA bovine serum albumin     -   cAMP 3′-5′ cyclic adenosine monophosphate     -   CHO Chinese hamster ovary     -   cM₅ cloned chimpanzee M₅ receptor     -   DCM dichloromethane (i.e., methylene chloride)     -   DIPEA N,N-diisopropylethylamine     -   dPBS Dulbecco's phosphate buffered saline     -   DMSO dimethyl sulfoxide     -   EDTA ethylenediaminetetraacetic acid     -   EtOAc ethyl acetate     -   EtOH ethanol     -   FBS fetal bovine serum     -   FLIPR fluorometric imaging plate reader     -   HATU O-(7-azabenzotriazol-1-yl-N,N,N′,N′-tetramethyluronium         hexafluorophosphate     -   HEPES 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid     -   hM₁ cloned human M₁ receptor     -   hM₂ cloned human M₂ receptor     -   hM₃ cloned human M₃ receptor     -   hM₄ cloned human M₄ receptor     -   hM₅ cloned human M₅ receptor     -   HPLC high-performance liquid chromatography     -   MCh methylcholine     -   MeOh methanol     -   TFA trifluoroacetic acid     -   THF tetrahydrofuran

Any other abbreviations used herein but not defined have their standard, generally accepted meaning. Unless noted otherwise, all materials, such as reagents, starting materials and solvents, were purchased from commercial suppliers (such as Sigma-Aldrich, Fluka, and the like) and were used without further purification.

Unless otherwise indicated, HPLC analysis was conducted using an Agilent (Palo Alto, Calif.) Series 1100 instrument equipped with a Zorbax Bonus RP 2.1×50 mm column (Agilent) having a 3.5 micron particle size. Detection was by UV absorbance at 214 nm. The mobile phases employed were as follows (by volume): A is ACN (2%), water (98%) and TFA (0.1%); and B is ACN (90%), water (10%) and TFA (0.1%). HPLC 10-70 data was obtained using a flow rate of 0.5 mL/minute of 10 to 70% B over a 6 minute gradient (with the remainder being A). Similarly, HPLC 5-35 data and HPLC 10-90 data were obtained using 5 to 35% B; or 10 to 90% B over a 5 minute gradient.

Liquid chromatography mass spectrometry (LCMS) data were obtained with an Applied Biosystems (Foster City, Calif.) Model API-150EX instrument. LCMS 10-90 data was obtained using 10 to 90% Mobile Phase B over-a 5 minute gradient.

Small-scale purification was conducted using an API 150EX Prep Workstation system from Applied Biosystems. The mobile phases employed were as follows (by volume): A is water and 0.05% TFA; and B is ACN and 0.05% TFA. For arrays (typically about 3 to 50 mg recovered sample size) the following conditions were used: 20 mL/min flow rate; 15 min gradients and a 20 mm×50 mm Prism RP column with 5 micron particles (Thermo Hypersil-Keystone, Bellefonte, Pa.). For larger scale purifications (typically greater than 100 mg crude sample), the following conditions were used: 60 mL/min flow rate; 30 min gradients and a 41.4 mm×250 mm Microsorb BDS column with 10 micron particles (Varian, Palo Alto, Calif.).

Preparation 1 Biphenyl-2-ylcarbamic Acid Piperidin-4-yl Ester

Biphenyl-2-isocyanate (97.5 g, 521 mmol) and 4-hydroxy-N-benzylpiperidine (105 g, 549 mmol) were heated together at 70° C. for 12 hours. The reaction mixture was then cooled to 50° C. and EtOH (1 L) was added and then 6M HCl (191 mL) was added slowly. The resulting mixture was then cooled to ambient temperature and ammonium formate (98.5 g, 1.56 mol) was added and then nitrogen gas was bubbled through the solution vigorously for 20 minutes. Palladium on activated carbon (20 g, 10 wt. % dry basis) was then added and the reaction mixture was heated at 40° C. for 12 hours, and then filtered through a pad of Celite. The solvent was then removed under reduced pressure and 1M HCl (40 mL) was added to the crude residue. The pH of the mixture was then adjusted with 10 N NaOH to pH 12. The aqueous layer was extracted with EtOAc (2×150 mL) and the organic layer was dried (magnesium sulfate), filtered and the solvent removed under reduced pressure to give 155 g of the title intermediate (100% yield). HPLC (10-70) R_(t)=2.52; m/z: [M+H⁺] calc'd for C₁₈H₂₀N₂O₂, 297.15; found, 297.3.

Preparation 2 3-[4-(Biphenyl-2-ylcarbamoyloxy)piperidin-1-yl]propionic Acid Methyl Ester

Methyl 3-bromopropionate (553 μL, 5.07 mmol) was added to a stirred solution of the product of Preparation 1 (1.00 g, 3.38 mmol) and DIPEA (1.76 mL, 10.1 mmol) in ACN (34 mL) at 50° C. and the reaction mixture was heated at 50° C. overnight. The solvent was then removed under reduced pressure, and the residue was dissolved in DCM (30 mL). The resulting solution was washed with saturated aqueous sodium bicarbonate solution (10 mL), dried (magnesium sulfate), filtered and the solvent was removed under reduced pressure. The crude residue was purified by column chromatography (5-10% MeOH/DCM) to give 905 mg of the title intermediate (70% yield).

Preparation 3 3-[4-(Biphenyl-2-ylcarbamoyloxy)piperidin-1-yl]propionic Acid

A stirred solution of the product of Preparation 2 (902 mg, 2.37 mmol) and lithium hydroxide (171 mg, 7.11 mmol) in 50% THF:H₂O (24 mL) was heated at 30° C. overnight, and then acidified with concentrated HCl and lyophilized to give the title intermediate (˜100% yield, also contains LiCl salts).

Preparation 3A 3-[4-(Biphenyl-2-ylcarbamoyloxy)piperidin-1-yl]propionic Acid

A solution of the product of Preparation 1 (50 g, 0.17 mmol) in 500 mL of DCM was treated with acrylic acid (17.43 mL, 0.254 mmol) at room temperature. The reaction mixture was then warmed to 50° C. and stirred overnight at that temperature. Some product was precipitated out at this point. The reaction mixture was concentrated to dryness. The crude product was stirred in MeOH (600 mL) at 75° C. for 2 hours before it was cooled to room temperature. After filtration, 60.68 g of the title intermediate was obtained (96% yield).

Preparation 4 Biphenyl-2-ylcarbamic Acid 1-[2-(4-Formylphenylcarbamoyl)ethyl]piperidin-4-yl Ester

A mixture of the product of Preparation 3 (1 g, 2.7 mmol), 4-aminobenzyl alcohol (498 mg, 4.05 mmol), HATU (1.54 g, 4.05 mmol) and DIPEA (1.41 mL, 8.1 mmol) in

DCM (14 mL) was stirred at room temperature for 2 hours. The reaction mixture was diluted with 100 mL of DCM and washed first with a 1:3 mixture of 1N HCl/water (100 mL), then brine (100 mL). The organic layer was dried over magnesium sulfate, filtered and concentrated. The residue was dissolved in DCM (100 mL) and the solution was cooled to −5° C. DIPEA (1.1 mL, 6.33 mmol) and DMSO (1.5 mL, 21.1 mmol) were added to the solution, followed by sulfur trioxide pyridine complex (1 g, 6.33 mmol). The reaction mixture was stirred at 0° C. for 1 hour then washed with a saturated solution of sodium bicarbonate (100 mL) and brine (100 mL). The organic layer was dried over magnesium sulfate, filtered and concentrated to give 0.84 g of the title intermediate (66% yield) as an oil.

Example 1 Biphenyl-2-ylcarbamic Acid 1-{2-[4-(4-Carbamoylpiperidin-1-ylmethyl)phenylcarbamoyl]ethyl}piperidin-4-yl Ester

Isonipecotamide (41 mg, 0.3 mmol) was added to a solution of the product of Preparation 4 (50 mg, 0.1 mmol) in 2 mL of MeOH. The reaction mixture was stirred at room temperature for 30 minutes and then sodium triacetoxyborohydride (67 mg, 0.3 mmol) was added. The resulting mixture was stirred for 2 hours at room temperature and then the solvent was removed in vacuo. The residue was purified using reverse phase HPLC to obtain 47.4 mg of the title compound (58% yield) as a bis(trifluoroacetate) salt. MS m/z [M+H⁺] calcd for C₃₄H₄₁N₅O₄ 584.3; found 584.3.

Using the procedures described herein and substituting the appropriate starting materials, the following compounds were prepared:

Example 2

Biphenyl-2-ylcarbamic acid 1-{2-[4-(4-carbamoylpiperidin-1-ylmethyl)-2-chloro-5-methoxyphenylcarbamoyl]ethyl}piperidin-4-yl ester; MS m/z [M+H⁺] calcd for C₃₅H₄₂ClN₅O₅, 648.3; found, 648.2.

Example 3

Biphenyl-2-ylcarbamic acid 1-{2-[4-(4-carbamoylpiperidin-1-ylmethyl)-3-methoxyphenylcarbamoyl]ethyl}piperidin-4-yl ester; MS m/z [M+H⁺] calcd for C₃₅H₄₃N₅O₅, 614.3; found, 614.4.

Example 4

Biphenyl-2-ylcarbamic acid 1-{2-[4-(4-carbamoyl-piperidin-1-ylmethyl)-3-hydroxyphenylcarbamoyl]ethyl}piperidin-4-yl ester; MS m/z [M+H⁺] calcd for C₃₄H₄₁N₅O₅, 600.3; found, 600.2.

In addition, the following compounds can be prepared using the procedures described herein and substituting the appropriate starting materials:

Example 5 Biphenyl-2-ylcarbamic acid 1-(2-{[4-(4-carbamoylpiperidin-1-ylmethyl)phenyl]methylcarbamoyl}ethyl)piperidin-4-yl ester Example 6 Biphenyl-2-ylcarbamic acid 1-{2-[4-(4-methylcarbamoylpiperidin-1-ylmethyl)phenylcarbamoyl]ethyl}piperidin-4-yl ester Example 7 Biphenyl-2-ylcarbamic acid 1-{2-[4-(4-ethylcarbamoylpiperidin-1-ylmethyl)phenylcarbamoyl]ethyl}piperidin-4-yl ester Example 8 Biphenyl-2-yl-carbamic acid 1-{2-[4-(4-propylcarbamoylpiperidin-1-ylmethyl)phenylcarbamoyl]ethyl}piperidin-4-yl ester Example 9 Biphenyl-2-yl-carbamic acid 1-{2-[4-(4-isopropylcarbamoylpiperidin-1-ylmethyl)phenylcarbamoyl]ethyl}piperidin-4-yl ester Example 10 Biphenyl-2-yl-carbamic acid 1-{2-[4-(4-carbamoylpiperidin-1-ylmethyl)-2-chlorophenylcarbamoyl]ethyl}piperidin-4-yl ester; and Example 11 Biphenyl-2-yl-carbamic acid 1-{2-[5-(4-carbamoylpiperidin-1-ylmethyl)thiophen-2-ylcarbamoyl]ethyl}piperidin-4-yl ester Assay 1 Radioligand Binding Assay

A. Membrane Preparation from Cells Expressing hM₁, hM₂, hM₃ and hM₄ Muscarinic Receptor Subtypes

CHO cell lines stably expressing cloned human hM₁, hM₂, hM₃ and hM₄ muscarinic receptor subtypes, respectively, were grown to near confluency in medium consisting of HAM's F-12 supplemented with 10% FBS and 250 μg/mL Geneticin. The cells were grown in a 5% CO₂, 37° C. incubator and lifted with 2 mM EDTA in dPBS. Cells were collected by 5 minute centrifugation at 650×g, and cell pellets were either stored frozen at −80° C. or membranes were prepared immediately. For membrane preparation, cell pellets were resuspended in lysis buffer and homogenized with a Polytron PT-2100 tissue disrupter (Kinematica AG; 20 seconds×2 bursts). Crude membranes were centrifuged at 40,000×g for 15 minutes at 4° C. The membrane pellet was then resuspended with resuspension buffer and homogenized again with the Polytron tissue disrupter. The protein concentration of the membrane suspension was determined by the method described in Lowry, O. et al., Journal of Biochemistry 193:265 (1951). All membranes were stored frozen in aliquots at −80° C. or used immediately. Aliquots of prepared hM₅ receptor membranes were purchased directly from Perkin Elmer and stored at −80° C. until use.

B. Radioligand Binding Assay on Muscarinic Receptor Subtypes hM₁, hM₂, hM₃, hM₄ and hM₅

Radioligand binding assays were performed in 96-well microtiter plates in a total assay volume of 100 μL. CHO cell membranes stably expressing either the hM₁, hM₂, hM₃, hM₄ or hM₅ muscarinic subtype were diluted in assay buffer to the following specific target protein concentrations (μg/well): 10 μg for hM₁, 10-15 μg for hM₂, 10-20 μg for hM₃, 10-20 μg for hM₄, and 10-12 μg for hM₅. The membranes were briefly homogenized using a Polytron tissue disruptor (10 seconds) prior to assay plate addition. Saturation binding studies for determining K_(D) values of the radioligand were performed using L-[N-methyl-³H]scopolamine methyl chloride ([³H]-NMS) (TRK666, 84.0 Ci/mmol, Amersham Pharmacia Biotech, Buckinghamshire, England) at concentrations ranging from 0.001 nM to 20 nM. Displacement assays for determination of K_(i) values of test compounds were performed with [³H]-NMS at 1 nM and eleven different test compound concentrations. The test compounds were initially dissolved to a concentration of 400 μM in dilution buffer and then serially diluted 5× with dilution buffer to final concentrations ranging from 10 pM to 100 μM. The addition order and volumes to the assay plates were as follows: 25 μL radioligand, 25 μL diluted test compound, and 50 μL membranes. Assay plates were incubated for 60 minutes at 37° C. Binding reactions were terminated by rapid filtration over GF/B glass fiber filter plates (PerkinElmer Inc., Wellesley, Mass.) pre-treated in 1% BSA. Filter plates were rinsed three times with wash buffer (10 mM HEPES) to remove unbound radioactivity. Plates were then air dried, and 50 μL Microscint-20 liquid scintillation fluid (PerkinElmer Inc., Wellesley, Mass.) was added to each well. The plates were then counted in a PerkinElmer Topcount liquid scintillation counter (PerkinElmer Inc., Wellesley, Mass.). Binding data were analyzed by nonlinear regression analysis with the GraphPad Prism Software package (GraphPad Software, Inc., San Diego, Calif.) using the one-site competition model. K_(i) values for test compounds were calculated from observed IC₅₀ values and the K_(D) value of the radioligand using the Cheng-Prusoff equation (Cheng Y; Prusoff W. H. Biochemical Pharmacology 22(23):3099-108 (1973)). K_(i) values were converted to pK_(i) values to determine the geometric mean and 95% confidence intervals. These summary statistics were then converted back to K_(i) values for data reporting.

In this assay, a lower K_(i) value indicates that the test compound has a higher binding affinity for the receptor tested. For example, the compound of Example 1 was found to have a K_(i) value of less than about 5 nM for the M₃ muscarinic receptor subtype in this assay.

Assay 2 Muscarinic Receptor Functional Potency Assays

A. Blockade of Agonist-Mediated Inhibition of cAMP Accumulation

In this assay, the functional potency of a test compound is determined by measuring the ability of the test compound to block oxotremorine-inhibition of forskolin-mediated cAMP accumulation in CHO-K1 cells expressing the hM₂ receptor.

cAMP assays are performed in a radioimmunoassay format using the Flashplate Adenylyl Cyclase Activation Assay System with ¹²⁵I-cAMP (NEN SMP004B, PerkinElmer Life Sciences Inc., Boston, Mass.), according to the manufacturer's instructions.

Cells are rinsed once with dPBS and lifted with Trypsin-EDTA solution (0.05% trypsin/0.53 mM EDTA) as described in the Cell Culture and Membrane Preparation section above. The detached cells are washed twice by centrifugation at 650×g for five minutes in 50 mLs dPBS. The cell pellet is then re-suspended in 10 mL dPBS, and the cells are counted with a Coulter Z1 Dual Particle Counter (Beckman Coulter, Fullerton, Calif.). The cells are centrifuged again at 650×g for five minutes and re-suspended in stimulation buffer to an assay concentration of 1.6×10⁶-2.8×10⁶ cells/mL.

The test compound is initially dissolved to a concentration of 400 μM in dilution buffer (dPBS supplemented with 1 mg/mL BSA (0.1%)), and then serially diluted with dilution buffer to final molar concentrations ranging from 100 μM to 0.1 nM. Oxotremorine is diluted in a similar manner.

To measure oxotremorine inhibition of adenylyl cyclase (AC) activity, 25 μL forskolin (25 μM final concentration diluted in dPBS), 25 μL diluted oxotremorine, and 50 μL cells are added to agonist assay wells. To measure the ability of a test compound to block oxotremorine-inhibited AC activity, 25 μL forskolin and oxotremorine (25 μM and 5 μM final concentrations, respectively, diluted in dPBS) 25 μL diluted test compound, and 50 μL cells are added to remaining assay wells.

Reactions are incubated for 10 minutes at 37° C. and stopped by addition of 100 μL ice-cold detection buffer. Plates are sealed, incubated overnight at room temperature and counted the next morning on a PerkinElmer TopCount liquid scintillation counter (PerkinElmer Inc., Wellesley, Mass.). The amount of cAMP produced (pmol/well) is calculated based on the counts observed for the samples and cAMP standards, as described in the manufacturer's user manual. Data are analyzed by nonlinear regression analysis with the GraphPad Prism Software package (GraphPad Software, Inc., San Diego, Calif.) using the non-linear regression, one-site competition equation. The Cheng-Prusoff equation is used to calculate the K_(i), using the EC₅₀ of the oxotremorine concentration-response curve and the oxotremorine assay concentration as the K_(D) and [L], respectively. The K_(i) values are converted to pK_(i) values to determine the geometric mean and 95% confidence intervals. These summary statistics are then converted back to K_(i) values for data reporting.

In this assay, a lower K_(i) value indicates that the test compound has a higher functional activity at the receptor tested. Compounds of this invention are expected to have a K_(i) value of less than about 10 nM for blockade of oxotremorine-inhibition of forskolin-mediated cAMP accumulation in CHO-K1 cells expressing the hM₂ receptor.

B. Blockade of Agonist-Mediated [³⁵S]GTPγS Binding

In a second functional assay, the functional potency of test compounds can be determined by measuring the ability of the compounds to block oxotremorine-stimulated [³⁵S]GTPγS binding in CHO-K1 cells expressing the hM₂ receptor.

At the time of use, frozen membranes are thawed and then diluted in assay buffer with a final target tissue concentration of 5-10 μg protein per well. The membranes are briefly homogenized using a Polytron PT-2100 tissue disrupter and then added to the assay plates.

The EC₉₀ value (effective concentration for 90% maximal response) for stimulation of [³⁵S]GTPγS binding by the agonist oxotremorine is determined in each experiment.

To determine the ability of a test compound to inhibit oxotremorine-stimulated [³⁵S]GTPγS binding, the following is added to each well of 96 well plates: 25 μL of assay buffer with [³⁵S]GTPγS (0.4 nM), 25 μL of oxotremorine (EC₉₀) and GDP (3 μM), 25 μL of diluted test compound and 25 μL CHO cell membranes expressing the hM₂ receptor. The assay plates are then incubated at 37° C. for 60 minutes. The assay plates are filtered over 1% BSA-pretreated GF/B filters using a PerkinElmer 96-well harvester. The plates are rinsed with ice-cold wash buffer for 3×3 seconds and then air or vacuum dried. Microscint-20 scintillation liquid (50 μL) is added to each well, and each plate is sealed and radioactivity counted on a topcounter (PerkinElmer). Data are analyzed by nonlinear regression analysis with the GraphPad Prism Software package (GraphPad Software, Inc., San Diego, Calif.) using the non-linear regression, one-site competition equation. The Cheng-Prusoff equation is used to calculate the K_(i), using the IC₅₀ values of the concentration-response curve for the test compound and the oxotremorine concentration in the assay as the K_(D) and [L], ligand concentration, respectively.

In this assay, a lower K_(i) value indicates that the test compound has a higher functional activity at the receptor tested. Compounds of this invention are expected to have a K_(i) value of less than about 10 nM for blockade of oxotremorine-stimulated [³⁵S]GTPγS binding in CHO-K1 cells expressing the hM₂ receptor.

C. Blockade of Agonist-Mediated Calcium Release via FLIPR Assays

Muscarinic receptor subtypes (M₁, M₃ and M₅ receptors), which couple to G_(q) proteins, activate the phospholipase C (PLC) pathway upon agonist binding to the receptor. As a result, activated PLC hydrolyzes phosphatyl inositol diphosphate (PIP₂) to diacylglycerol (DAG) and phosphatidyl-1,4,5-triphosphate (IP₃), which in turn generates calcium release from intracellular stores, i.e., endoplasmic and sarcoplasmic reticulum. The FLIPR (Molecular Devices, Sunnyvale, Calif.) assay capitalizes on this increase in intracellular calcium by using a calcium sensitive dye (Fluo-4AM, Molecular Probes, Eugene, Oreg.) that fluoresces when free calcium binds. This fluorescence event is measured in real time by the FLIPR, which detects the change in fluorescence from a monolayer of cells cloned with human M₁ and M₃, and chimpanzee M₅ receptors. Antagonist potency can be determined by the ability of antagonists to inhibit agonist-mediated increases in intracellular calcium.

For FLIPR calcium stimulation assays, CHO cells stably expressing the hM₁, hM₃ and cM₅ receptors are seeded into 96-well FLIPR plates the night before the assay is done. Seeded cells are washed twice by Cellwash (MTX Labsystems, Inc.) with FLIPR buffer (10 mM HEPES, pH 7.4, 2 mM calcium chloride, 2.5 mM probenecid in Hank's Buffered Salt Solution (HBSS) without calcium and magnesium) to remove growth media and leaving 50 μL/well of FLIPR buffer. The cells are then incubated with 50 μL/well of 4 μM FLUO-4AM (a 2× solution was made) for 40 minutes at 37° C., 5% carbon dioxide. Following the dye incubation period, cells are washed two times with FLIPR buffer, leaving a final volume of 50 μL/well.

To determine antagonist potency, the dose-dependent stimulation of intracellular Ca²⁺ release for oxotremorine is first determined so that antagonist potency can later be measured against oxotremorine stimulation at an EC₉₀ concentration. Cells are first incubated with compound dilution buffer for 20 minutes, followed by agonist addition, which is performed by the FLIPR. An EC₉₀ value for oxotremorine is generated according to the method detailed in the FLIPR measurement and data reduction section below, in conjunction with the formula EC_(F)=((F/100−F)^1/H)*EC₅₀. An oxotremorine concentration of 3×EC_(F) is prepared in stimulation plates such that an EC₉₀ concentration of oxotremorine is added to each well in the antagonist inhibition assay plates.

The parameters used for the FLIPR are: exposure length of 0.4 seconds, laser strength of 0.5 watts, excitation wavelength of 488 nm, and emission wavelength of 550 nm. Baseline is determined by measuring the change in fluorescence for 10 seconds prior to addition of agonist. Following agonist stimulation, the FLIPR continuously measured the change of fluorescence every 0.5 to 1 second for 1.5 minutes to capture the maximum fluorescence change.

The change of fluorescence is expressed as maximum fluorescence minus baseline fluorescence for each well. The raw data is analyzed against the logarithm of drug concentration by nonlinear regression with GraphPad Prism (GraphPad Software, Inc., San Diego, Calif.) using the built-in model for sigmoidal dose-response. Antagonist K_(i) values are determined by Prism using the oxotremorine EC₅₀ value as the K_(D) and the oxotremorine EC₉₀ for the ligand concentration according to the Cheng-Prusoff equation (Cheng & Prusoff, 1973).

In this assay, a lower K_(i) value indicates that the test compound has a higher functional activity at the receptor tested. Compounds of this invention are expected to have a K_(i) value of less than about 10 nM for blockade of agonist-mediated calcium release in CHO cells stably expressing the hM₃ receptor.

Assay 3 Determination of Duration of Bronchoprotection in Guinea Pig Model of Acetylcholine-Induced Bronchoconstriction

This in vivo assay is used to assess the bronchoprotective effects of test compounds exhibiting muscarinic receptor antagonist activity.

Groups of six male guinea pigs (Duncan-Hartley (HsdPoc:DH) Harlan, Madison, Wis.) weighing between 250 and 350 g are individually identified by cage cards. Throughout the study animals are allowed access to food and water ad libitum.

Test compounds are administered via inhalation over 10 minutes in a whole-body exposure dosing chamber (R&S Molds, San Carlos, Calif.). The dosing chambers are arranged so that an aerosol was simultaneously delivered to 6 individual chambers from a central manifold. Guinea pigs are exposed to an aerosol of a test compound or vehicle (WFI). These aerosols are generated from aqueous solutions using an LC Star Nebulizer Set (Model 22F51, PARI Respiratory Equipment, Inc. Midlothian, Va.) driven by a mixture of gases (CO₂=5%, O₂=21% and N₂=74%) at a pressure of 22 psi. The gas flow through the nebulizer at this operating pressure is approximately 3 L/minute. The generated aerosols are driven into the chambers by positive pressure. No dilution air is used during the delivery of aerosolized solutions. During the 10 minute nebulization, approximately 1.8 mL of solution is nebulized. This is measured gravimetrically by comparing pre- and post-nebulization weights of the filled nebulizer.

The bronchoprotective effects of test compounds administered via inhalation are evaluated using whole body plethysmography at 1.5, 24, 48 and 72 hours post-dose.

Forty-five minutes prior to the start of the pulmonary evaluation, each guinea pig is anesthetized with an intramuscular injection of ketamine (43.75 mg/kg), xylazine (3.50 mg/kg) and acepromazine (1.05 mg/kg). After the surgical site is shaved and cleaned with 70% alcohol, a 2-3 cm midline incision of the ventral aspect of the neck was made. Then, the jugular vein is isolated and cannulated with a saline-filled polyethylene catheter (PE-50, Becton Dickinson, Sparks, Md.) to allow for intravenous infusions of ACh (Sigma-Aldrich, St. Louis, Mo.) in saline. The trachea is then dissected free and cannulated with a 14 G teflon tube (#NE-014, Small Parts, Miami Lakes, Fla.). If required, anesthesia is maintained by additional intramuscular injections of the aforementioned anesthetic mixture. The depth of anesthesia is monitored and adjusted if the animal responds to pinching of its paw or if the respiration rate is greater than 100 breaths/minute.

Once the cannulations are complete, the animal is placed into a plethysmograph (#PLY3114, Buxco Electronics, Inc., Sharon, Conn.) and an esophageal pressure cannula (PE-160, Becton Dickinson, Sparks, Md.) is inserted to measure pulmonary driving pressure (pressure). The teflon tracheal tube is attached to the opening of the plethysmograph to allow the guinea pig to breathe room air from outside the chamber. The chamber is then sealed. A heating lamp is used to maintain body temperature and the guinea pig's lungs are inflated 3 times with 4 mL of air using a 10 mL calibration syringe (#5520 Series, Hans Rudolph, Kansas City, Mo.) to ensure that the lower airways do not collapse and that the animal does not suffer from hyperventilation.

Once it is determined that baseline values are within the range 0.3-0.9 mL/cm H₂O for compliance and within the range 0.1-0.199 cm H₂O/mL per second for resistance, the pulmonary evaluation is initiated. A Buxco pulmonary measurement computer program enables the collection and derivation of pulmonary values.

Starting this program initiates the experimental protocol and data collection. The changes in volume over time that occur within the plethysmograph with each breath are measured via a Buxco pressure transducer. By integrating this signal over time, a measurement of flow is calculated for each breath. This signal, together with the pulmonary driving pressure changes, which are collected using a Sensym pressure transducer (#TRD4100), is connected via a Buxco (MAX 2270) preamplifier to a data collection interface (#'s SFT3400 and SFT3813). All other pulmonary parameters are derived from these two inputs.

Baseline values are collected for 5 minutes, after which time the guinea pigs are challenged with ACh. ACh (0.1 mg/mL) is infused intravenously for 1 minute from a syringe pump (sp210iw, World Precision Instruments, Inc., Sarasota, Fla.) at the following doses and prescribed times from the start of the experiment: 1.9 μg/minute at 5 minutes, 3.8 μg/minute at 10 minutes, 7.5 μg/minute at 15 minutes, 15.0 μg/minute at 20 minutes, 30 μg/minute at 25 minutes and 60 μg/minute at 30 minutes. If resistance or compliance has not returned to baseline values at 3 minutes following each ACh dose, the guinea pig's lungs are inflated 3 times with 4 mL of air from a 10 mL calibration syringe. Recorded pulmonary parameters includes respiration frequency (breaths/minute), compliance (mL/cm H₂O) and pulmonary resistance (cm H₂O/mL per second). Once the pulmonary function measurements are completed at minute 35 of this protocol, the guinea pig is removed from the plethysmograph and euthanized by carbon dioxide asphyxiation.

The data are evaluated in one or both of the following ways:

(a) Pulmonary resistance (R_(L), cm H₂O/mL per second) is calculated from the ratio of “change in pressure” to “the change in flow.” The R_(L) response to ACh (60 μg/min, IH) is computed for the vehicle and the test compound groups. The mean ACh response in vehicle-treated animals, at each pre-treatment time, is calculated and used to compute % inhibition of ACh response, at the corresponding pre-treatment time, at each test compound dose. Inhibition dose-response curves for ‘R_(L)’ are fitted with a four parameter logistic equation using GraphPad Prism, version 3.00 for Windows (GraphPad Software, San Diego, Calif.) to estimate bronchoprotective ID₅₀ (dose required to inhibit the ACh (60 μg/min) bronchoconstrictor response by 50%). The equation used is as follows: Y=Min+(Max−Min)/(1+10^(((log ID50−X)*Hillslope))) where X is the logarithm of dose, Y is the response (% Inhibition of ACh induced increase in R_(L)). Y starts at MM and approaches asymptotically to Max with a sigmoidal shape.

(b) The quantity PD₂, which is defined as the amount of ACh or histamine needed to cause a doubling of the baseline pulmonary resistance, is calculated using the pulmonary resistance values derived from the flow and the pressure over a range of ACh or histamine challenges using the following equation (which is derived from a equation used to calculate PC₂₀ values described in American Thoracic Society. Guidelines for methacholine and exercise challenge testing—1999. Am J Respir Crit Care Med. 161: 309-329 (2000)):

${PD}_{2} = {{antilog}\;\left\lbrack {{\log\mspace{11mu} C_{1}} + \frac{\left( {{\log\mspace{11mu} C_{2}} - {\log\mspace{11mu} C_{1}}} \right)\left( {{2\; R_{0}} - R_{1}} \right)}{R_{2} - R_{1}}} \right\rbrack}$ where:

-   -   C₁=concentration of ACh or histamine preceding C₂     -   C₂=concentration of ACh or histamine resulting in at least a         2-fold increase in pulmonary resistance (R_(L))     -   R₀=Baseline R_(L) value     -   R₁=R_(L) value after C₁     -   R₂=R_(L) value after C₂         An efficacious dose is defined as a dose that limits the         bronchrestriction response to a 50 μg/mL dose of ACh to a         doubling of the baseline pulmonary resistance (PD₂₍₅₀₎).

Statistical analysis of the data is performed using a two-tailed Students t-test. A P-value<0.05 is considered significant.

Generally, test compounds having a PD₂₍₅₀₎ less than about 200 μg/mL for ACh-induced bronchoconstriction at 1.5 hours post-dose in this assay are preferred. Compounds of the invention are expected to have a PD₂₍₅₀₎ of less than about 200 μg/mL for ACh-induced bronchoconstriction at 1.5 hours post-dose.

Assay 4 Inhalation Guinea Pig Salivation Assay

Guinea pigs (Charles River, Wilmington, Mass.) weighing 200-350 g are acclimated to the in-house guinea pig colony for at least 3 days following arrival. Test compound or vehicle are dosed via inhalation (IH) over a 10 minute time period in a pie shaped dosing chamber (R&S Molds, San Carlos, Calif.). Test solutions are dissolved in sterile water and delivered using a nebulizer filled with 5.0 mL of dosing solution. Guinea pigs are restrained in the inhalation chamber for 30 minutes. During this time, guinea pigs are restricted to an area of approximately 110 sq. cm. This space is adequate for the animals to turn freely, reposition themselves, and allow for grooming. Following 20 minutes of acclimation, guinea pigs are exposed to an aerosol generated from a LS Star Nebulizer Set (Model 22F51, PART Respiratory Equipment, Inc. Midlothian, Va.) driven by house air at a pressure of 22 psi. Upon completion of nebulization, guinea pigs are evaluated at 1.5, 6, 12, 24, 48, or 72 hrs after treatment.

Guinea pigs are anesthetized one hour before testing with an intramuscular (IM) injection of a mixture of ketamine 43.75 mg/kg, xylazine 3.5 mg/kg, and acepromazine 1.05 mg/kg at an 0.88 mL/kg volume. Animals are placed ventral side up on a heated (37° C.) blanket at a 20 degree incline with their head in a downward slope. A 4-ply 2×2 inch gauze pad (Nu-Gauze General-use sponges, Johnson and Johnson, Arlington, Tex.) is inserted in the guinea pig's mouth. Five minutes later, the muscarinic agonist pilocarpine (3.0 mg/kg, SC) is administered and the gauze pad is immediately discarded and replaced by a new pre-weighed gauze pad. Saliva is collected for 10 minutes, at which point the gauze pad was weighed and the difference in weight recorded to determine the amount of accumulated saliva (in mg). The mean amount of saliva collected for animals receiving the vehicle and each dose of test compound is calculated. The vehicle group mean is considered to be 100% salivation. Results are calculated using result means (n=3 or greater). Confidence intervals (95%) are calculated for each dose at each time point using two-way ANOVA. This model is a modified version of the procedure described in Rechter, “Estimation of anticholinergic drug effects in mice by antagonism against pilocarpine-induced salivation” Ata Pharmacol Toxicol 24:243-254 (1996).

The mean weight of saliva in vehicle-treated animals, at each pre-treatment time, is calculated and used to compute % inhibition of salivation, at the corresponding pre-treatment time, at each dose. The inhibition dose-response data are fitted to a four parameter logistic equation using GraphPad Prism, version 3.00 for Windows (GraphPad Software, San Diego, Calif.) to estimate anti-sialagogue ID₅₀ (dose required to inhibit 50% of pilocarpine-evoked salivation). The equation used is as follows: Y=Min+(Max−Min)/(1+10^(((log ID50−X)*Hillslope))) where X is the logarithm of dose, Y is the response (% inhibition of salivation). Y starts at Min and approaches asymptotically to Max with a sigmoidal shape.

The ratio of the anti-sialagogue ID₅₀ to bronchoprotective ID₅₀ was used to compute the apparent lung-selectivity index of the test compound. Generally, compounds having an apparent lung-selectivity index greater than about 5 are preferred. In this assay, compounds of the invention are expected to have an apparent lung-selectivity index greater than 5.

Assay 5 Methacholine-Induced Depressor Responses in Conscious Guinea Pigs

Healthy, adult, male Sprague-Dawley guinea pigs (Harlan, Indianapolis, Ind.), weighing between 200 and 300 g are used in these studies. Under isoflurane anesthesia (to effect), animals are instrumented with common carotid artery and jugular vein catheters (PE-50 tubing). The catheters are exteriorized utilizing a subcutaneous tunnel to the subscapular area. All surgical incisions are sutured with 4-0 Ethicon Silk and the catheters locked with heparin (1000 units/mL). Each animal is administered saline (3 mL, SC) at the end of surgery as well as buprenorphine (0.05 mg/kg, IM). Animals are allowed to recover on a heating pad before being returned to their holding rooms.

Approximately 18 to 20 hours following surgery, the animals are weighed and the carotid artery catheter on each animal is connected to a transducer for recording arterial pressure. Arterial pressure and heart rate are recorded using a Biopac MP-100 Acquisition System. Animals are allowed t6 acclimate and stabilize for a period of 20 minutes.

Each animal is challenged with MCh (0.3 mg/kg, IV) administered through the jugular venous line and the cardiovascular response is monitored for 10 minutes. The animals are then placed into the whole body dosing chamber, which is connected to a nebulizer containing the test compound or vehicle solution. The solution is nebulized for 10 minutes using a gas mixture of breathable air and 5% carbon dioxide with a flow rate of 3 liters/minute. The animals are then removed from the whole body chamber and returned to their respective cages. At 1.5 and 24 h post-dosing, the animals are re-challenged with MCh (0.3 mg/kg, IV) and the hemodynamic response is determined. Thereafter, the animals are euthanized with sodium pentobarbital (150 mg/kg, IV).

MCh produces a decrease in mean arterial pressure (MAP) and decrease in heart rate (bradycardia). The peak decrease, from baseline, in MAP (depressor responses) is measured for each MCh challenge (before and after IH dosing). The effects of treatment on the MCh responses are expressed as % inhibition (mean+/−SEM) of the control depressor responses. Two-way ANOVA with the appropriate post-hoc test is used to test the effects of treatment and pre-treatment time. The depressor responses to MCh are expected to be relatively unchanged at 1.5 and 24 h after inhalation dosing with vehicle.

The ratio of the anti-depressor ID₅₀ to bronchoprotective ID₅₀ is used to compute apparent lung-selectivity of the test compound. Generally, compounds having an apparent lung-selectivity index greater than 5 are preferred. It is expected that the compounds of the invention will exhibit an apparent lung-selectivity index greater than 5, as measured in this assay.

While the present invention has been described with reference to specific aspects or embodiments thereof, it will be understood by those of ordinary skilled in the art that various changes can be made or equivalents can be substituted without departing from the true spirit and scope of the invention. Additionally, to the extent permitted by applicable patent statues and regulations, all publications, patents and patent applications cited herein are hereby incorporated by reference in their entirety to the same extent as if each document had been individually incorporated by reference herein. 

1. A compound of formula I:

wherein: a is 0 or 1; R¹ is halo; b is 0 or 1; R² is halo; m is 0 or 1; R⁴ is selected from hydrogen and (1-4C)alkyl; s is 0, 1 or 2; Ar¹ represents a phenylene group substituted with (R⁵)_(q) where q is 0 or an integer from 1 to 4 and each R⁵ is selected independently from halo, hydroxy, (1-4C)alkyl, and (1-4C)alkoxy; t is 0, 1 or 2; n is 1; p is 0 or 1; and R⁷ and R⁸ are independently hydrogen or (1-4C)alkyl; wherein each alkyl and alkoxy group in R⁵, R⁷, and R⁸ is optionally substituted with 1 to 5 fluoro substituents; or a pharmaceutically acceptable salt or stereoisomer thereof.
 2. The compound of claim 1, wherein a and b each represent
 0. 3. The compound of claim 1, wherein m and s each represents 0, and t is
 1. 4. The compound of claim 1, wherein the —CONR⁷R⁸ group is in the para position and p represents
 0. 5. The compound of claim 1, wherein Ar¹ represents phen-1,4-ylene, wherein the phenylene group is optionally substituted with one or two R⁵ substituents.
 6. The compound of claim 5 where q is
 0. 7. The compound of claim 5 wherein q is 1 or 2 and R⁵ is selected independently from hydroxy, halo, (1-4C)alkyl, and (1-4C)alkoxy, wherein each alkyl and alkoxy group is optionally substituted with from 1 to 3 fluoro substituents.
 8. The compound of claim 1 wherein a, b, m, p, and s each represent 0; t is 1; Ar¹ represents phen-1,4-ylene optionally substituted with one or two R⁵ substituents; and the —CONR⁷R⁸ group is in the para position.
 9. The compound of claim 1, wherein R⁴ is hydrogen or methyl.
 10. The compound of claim 1, wherein R⁸ is hydrogen.
 11. The compound of claim 10, wherein R⁷ is hydrogen.
 12. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound of claim
 1. 